WASHINGTON - Neil Heslin, whose son Jesse McCord Lewis was killed in the mass shooting in Newtown, Conn., gave moving testimony on Wednesday during a Senate Judiciary Committee hearing on the assault weapons ban proposed by Sen. Dianne Feinstein (D-Calif.).

"As Jesse was getting out of the truck [the morning he died], he leaned in and hugged me," Heslin said, weeping openly as he held up a portrait of his son. "I can still feel that hug, and that pat on the back. He said, 'everything's going to be ok, Dad, it's all going to be ok.' And it wasn't ok."

The night of the shooting, Heslin said, "I waited in that firehouse until one in the morning, until I knew Jesse was confirmed dead ... I have to go home at night to an empty house, without my son."

Heslin's son Jesse was one of the 20 children and six educators who were shot and killed at Sandy Hook Elementary School in mid-December. A group of Newtown residents attended the hearing, and sat behind Heslin as he spoke. The hearing room was silent except for the sound of weeping.

Heslin has spoken about his son's death before, during a public hearing in Connecticut in late January. Gun rights activists in the audience at that hearing shouted "Second Amendment!" at Heslin when he questioned why civilians should be permitted to carry military-style assault weapons.

The tragedy at Sandy Hook has galvanized public support for stricter gun controls, and Feinstein's bill is the most ambitious of a number of proposals currently under consideration by the Senate. Other proposals include an expansion of the background check system to cover all gun purchases, and a ban on high-capacity gun magazines.

Other witnesses testifying alongside Heslin included Western Connecticut Health Network EMS medical director Dr. William Begg, who treated some of the victims of Sandy Hook; Fordham Law School professor Nicholas Johnson; attorney David Hardy of Tucson, Ariz.; former Republican Florida Rep. Sandy Adams; and Mayor of Philadelphia Michael Nutter.

Michael McAuliff contributed reporting.

Earlier on HuffPost:

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  • Barack Obama

    President Barack Obama arrives at the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Barack Obama

    President Barack Obama greets Gov. Dannel Malloy during his arrival at the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/The Hartford Courant, Stephen Dunn, Pool)

  • Barack Obama

    President Barack Obama pauses during a speech at an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • Barack Obama

    President Barack Obama walks off after delivering a speech at an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Barack Obama

    President Barack Obama speaks during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • Barack Obama

    President Barack Obama greets State Senate Minority Leader John McKinney, R-Fairfield, on his arrival, before the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting inside the Newtown High School auditorium in Newtown, Conn., Sunday night, Dec. 16, 2012. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. (AP Photo/The Hartford Courant, Stephen Dunn, Pool)

  • Barack Obama

    President Barack Obama pauses as he delivers a speech during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Barack Obama

    President Barack Obama speaks during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/The Hartford Courant, Stephen Dunn, Pool)

  • Barack Obama

    President Barack Obama pauses as he delivers a speech at an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Barack Obama

    Residents pray during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • Barack Obama

    President Barack Obama pauses as he delivers a speech at an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • Barack Obama

    President Barack Obama pauses as he delivers a speech at an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School on Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • US-SCHOOL-SHOOTING-MEMORIAL

    US President Barack Obama makes his way off the stage after speaking at a memorial service for the victims and relatives of the Sandy Hook Elementary School shooting on December 16, 2012 at the Newtown High SChool in Newtown, Connecticut. Twenty-six people were killed when a gunman entered Sandy Hook Elementary and began a shooting spree. AFP PHOTO/Mandel NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)

  • Barack Obama

    President Barack Obama walks off stage after delivering a speech at an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School on Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Barack Obama

    President Barack Obama pauses as he delivers a speech during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school on Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • US-SCHOOL-SHOOTING-MEMORIAL

    US President Barack Obama pauses as he speaks during a memorial service for the victims and relatives of the Sandy Hook Elementary School shooting on December 16, 2012 in Newtown, Connecticut. Twenty-six people were killed when a gunman entered Sandy Hook Elementary and began a shooting spree. AFP PHOTO/Mandel NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)

  • Barack Obama

    President Barack Obama returns to the White House in Washington after attending an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School on Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jacquelyn Martin)

  • Barack Obama

    Residents greet each other before the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Barack Obama

    Air Force One carrying President Barack Obama is seen leaving Bradley Air National Guard Base in East Granby, Conn., Sunday, Dec. 16, 2012. The president was in Connecticut to attend a memorial for the victims of the Sandy Hook Elementary School shooting where 26 people, including 20 children, were killed Friday. (AP Photo/Jessica Hill)

  • Julie LaPak, right, and Scott Emslie, of Newton, Conn., watch President Obama delver his speech at the Iron Bridge restaurant, Sunday, Dec. 16, 2012 in Newtown, Conn. (AP Photo/Mary Altaffer)

  • A mourner looks on during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Surendra Khera, left, Manjaree Daw, center and Indira Khera, of Simsbury, Conn., watch President Obama deliver his speech at the Iron Bridge restaurant, Sunday, Dec. 16, 2012 in Newtown, Conn. The president spoke during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Mary Altaffer)

  • Barack Obama

    Residents look on as President Barack Obama delivers remarks at an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • A mourner weeps while listening to President Barack Obama speak on a loudspeaker while sitting outside a memorial at Newtown High School for the victims of the Sandy Hook Elementary School shooting, Sunday, Dec. 16, 2012, in Newtown, Conn. (AP Photo/David Goldman)

  • C.J. Singh, center, and other members of the Sikh community hold a candlelight vigil outside Newtown High School before an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Residents hold a candlelight vigil outside Newtown High School after President Barack Obama delivered remarks at an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • A young boy places a candle with others at the base of a flagpole outside Newtown High School before an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Eknoor Kaur, 3, stands with her father Guramril Singh during a candlelight vigil outside Newtown High School before an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Members of the Sikh community hold a candlelight vigil outside Newtown High School before an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • U.S. Sen. Joseph Lieberman, I-Conn., top right, Rep. Rosa DeLauro, D-Conn., left, Sen-elect Chris Murphy, center, and Lt. Gov. Nancy Wyman, right, wait for the arrival of President Barack Obama before the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting inside the Newtown High School auditorium in Newtown, Conn., Sunday night, Dec. 16, 2012. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. (AP Photo/The Hartford Courant, Stephen Dunn, Pool)

  • Residents look on during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. President Barack Obama is schedule to speak during the vigil. (AP Photo/ Evan Vucci)

  • Barack Obama

    Residents greet each other before the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. President Barack Obama is scheduled to speak during the vigil. (AP Photo/ Evan Vucci)

  • Barack Obama

    Residents greet each other before the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the school Friday and opened fire, killing 26 people, including 20 children. President Barack Obama is to scheduled to speak at the event. (AP Photo/ Evan Vucci)

  • Residents look on during an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. President Barack Obama is scheduled to speak during the vigil. (AP Photo/Evan Vucci)

  • Barack Obama

    Residents greet each other before the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • People wait in line to attend an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Barack Obama

    Residents greet each other before the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • People arrive at Newtown High School to attend an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown on Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Residents greet each other before the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Kayla Hopson and her daughter Lilliana, 9, left, and Janine Caswell and her daughter Genesis, 8, stand wrapped in Red Cross blankets to protect themselves from the cold, rainy weather as they wait in line to attend an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Residents wait for the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Eight-year old Shayne Frate, a third grade student at Sandy Hook Elementary School, hangs from her mother Valerie's back, wrapped in a Red Cross blanket to protect her from the cold, rainy weather, as she waits in line to attend an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • People wait in line to attend an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown on Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Residents wait for the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Red Cross volunteer Michael Cianciolo distributes blankets to protect people from the cold, rainy weather as they wait in line to attend an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Red Cross personnel provide blankets, water, snacks and even stuffed toys to keep people comfortable as they wait in line to attend an interfaith vigil with President Barack Obama, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Jason DeCrow)

  • Residents wait for the start of an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/Evan Vucci)

  • Barack Obama

    Residents greet each other before an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012 at Newtown High School in Newtown, Conn. A gunman walked into Sandy Hook Elementary School Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • Barack Obama

    Residents greet each other before an interfaith vigil for the victims of the Sandy Hook Elementary School shooting on Sunday, Dec. 16, 2012, at Newtown High School in Newtown, Conn. A gunman walked into the elementary school Friday and opened fire, killing 26 people, including 20 children. (AP Photo/ Evan Vucci)

  • A U.S. flag flies at half staff outside the Newtown High School before President Barack Obama is scheduled to attend a memorial for the victims of the Sandy Hook Elementary School shooting, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/David Goldman)

  • People wait in line to enter Newtown High School for a memorial vigil attended by President Barack Obama for the victims of the Sandy Hook Elementary School shooting, Sunday, Dec. 16, 2012, in Newtown, Conn. A gunman walked into Sandy Hook Elementary School in Newtown Friday and opened fire, killing 26 people, including 20 children. (AP Photo/David Goldman)