An attorney for Trayvon Martin's family expressed concern over the role Robert Zimmerman, the father of the man who shot and killed Martin, may have played in the investigation of the shooting.

In an interview with ThinkProgress, Natalie Jackson said that the elder Zimmerman, a former magistrate judge, understands "“what probable cause needs to be” in order to arrest a suspect or to issue a warrant. Robert Zimmerman was present when the police questioned his son the day after the shooting and re-enacted the incident.

Jackson told ThinkProgress that the elder Zimmerman's presence was possibly inappropriate because "we don't know what coaching went on."

In the minutes before the shooting, George Zimmerman called 911 to report that Martin, a 17-year-old from Miami Gardens, Fl., as "suspicious." Martin was unarmed, and was returning home from a convenience store that evening, carrying his cellphone, $22 in his wallet, a bag of Skittles and a can of iced tea. Zimmerman admitted to shooting and killing Martin, after a confrontation. Zimmerman, who claimed self-defense, was not charged or arrested in the shooting. Activists from around the country have held rallies and protests to call for charges to be brought against Zimmerman.

On Monday, Benjamin Crump, who represents Martin's family along with Jackson, sent a letter to the Justice Department which said that on the night of the shooting "family members of shooter George Zimmerman were present at the police department."

Last week, Robert Zimmerman appeared on a local television news broadcast to defend his son. In addition to reporting a threat Martin allegedly made to Zimmerman just before he was shot — which did not appear in the police report — he said that his role as a magistrate judge had little bearing on the investigation.

"Do you think being a judge affected this case in any way?" the reporter asked. "Do you think they gave George an easier time because of this?"

Robert Zimmerman said it did not. "No one knew that I was a retired magistrate judge. I didn't mention it to the police, I didn't mention it to the state attorney's office. Somehow the press picked up on it, but I've never mentioned it to anyone."

Robert Zimmerman added that had a similar case come before him in his role as a magistrate judge, a warrant "would absolutely be denied."

CORRECTION: An earlier version of this story incorrectly identified Benjamin Crump, the lawyer for the Martin family.

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  • Trayvon Martin Photos

    Benjamin Crump, attorney, for the family of the late Trayvon Martin, talks to the media after the release of 911 call at the Sanford City Hall on Friday, March 16, 2012 in Sanford, Fla. Martin, 17, was shot to death after being confronted by Sanford neighborhood watch volunteer George Zimmerman, 28, on February 26, 2012. Zimmerman told Sanford Police that he shot the unarmed black teenager in self-defense. Family members are calling for Zimmerman's arrest. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    Benjamin Crump, attorney, for the family of the late Trayvon Martin, talks to the media after the release of 911 call at the Sanford City Hall on Friday, March 16, 2012 in Sanford, Fla. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    Benjamin Crump, attorney, for the family of the late Trayvon Martin, talks to the media after the release of 911 call at the Sanford City Hall on Friday, March 16, 2012 in Sanford, Fla. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    A memorial for the late Trayvon Martin sits at the neighborhood where he was shot on Friday, March 16, 2012 in Sanford, Fla. Martin, 17, was shot to death after being confronted by Sanford neighborhood watch volunteer George Zimmerman, 28, on February 26, 2012. Zimmerman, white, told Sanford Police that he shot the unarmed black teenager in self-defense. Family members are calling for Zimmerman's arrest. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    Local historian and activist Francis Oliver adjusts a memorial she placed for the late Trayvon Martin at the neighborhood where he was shot on Friday, March 16, 2012 in Sanford, Fla. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    Valera Pinkard, of Orlando, Fla., holds a sign near a memorial for the late Trayvon Martin at the neighborhood where he was shot on Friday, March 16, 2012 in Sanford, Fla. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    Sybrina Fulton, mother, of the late Trayvon Martin, addresses the media with Martin's father Tracy Martin, left, on Friday, March 16, 2012 in Orlando, Fla. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    Sybrina Fulton, mother, of the late Trayvon Martin, left, hugs Selma Mora Lamilla, after addressing the media on Friday, March 16, 2012 in Orlando, Fla. Credit: David Manning for The Huffington Post

  • Tracy Martin, father, of the late Trayvon Martin, addresses the media on Friday, March 16, 2012 in Orlando, Fla. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    Benjamin Crump, attorney for the family of the late Trayvon Martin, addresses the media on Friday, March 16, 2012 in Orlando, Fla. Credit: David Manning for The Huffington Post

  • Trayvon Martin Photos

    Tracy Martin, father, of the late Trayvon Martin, addresses the media on Friday, March 16, 2012 in Orlando, Fla. Credit: David Manning for The Huffington Post

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Supporters of Trayvon Martin rally in Union Square during a 'Million Hoodie March' in Manhattan on March 21, 2012 in New York City. Thousands of protesters turned out to demonstrate against the killing of the black unarmed teenager by a white neighborhood watch captain. The protesters marched through the streets after holding a large rally in Union Square. (Photo by Mario Tama/Getty Images)

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Supporters of Trayvon Martin rally in Union Square during a 'Million Hoodie March' in Manhattan on March 21, 2012 in New York City. Thousands of protesters turned out to demonstrate against the killing of the black unarmed teenager by a white neighborhood watch captain. The protesters marched through the streets after holding a large rally in Union Square. (Photo by Mario Tama/Getty Images)

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Supporters of Trayvon Martin rally in Union Square during a 'Million Hoodie March' in Manhattan on March 21, 2012 in New York City. Thousands of protesters turned out to demonstrate against the killing of the black unarmed teenager by a white neighborhood watch captain. The protesters marched through the streets after holding a large rally in Union Square. (Photo by Mario Tama/Getty Images)

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Supporters of Trayvon Martin rally in Union Square during a 'Million Hoodie March' in Manhattan on March 21, 2012 in New York City. Thousands of protesters turned out to demonstrate against the killing of the black unarmed teenager by a white neighborhood watch captain. The protesters marched through the streets after holding a large rally in Union Square. (Photo by Mario Tama/Getty Images)

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Supporters of Trayvon Martin rally in Union Square during a 'Million Hoodie March' in Manhattan on March 21, 2012 in New York City. Thousands of protesters turned out to demonstrate against the killing of the black unarmed teenager by a white neighborhood watch captain. The protesters marched through the streets after holding a large rally in Union Square. (Photo by Mario Tama/Getty Images)

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Supporters of Trayvon Martin rally in Union Square during a 'Million Hoodie March' in Manhattan on March 21, 2012 in New York City. Thousands of protesters turned out to demonstrate against the killing of the black unarmed teenager by a white neighborhood watch captain. The protesters marched through the streets after holding a large rally in Union Square. (Photo by Mario Tama/Getty Images)

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Supporters of Trayvon Martin block traffic as they march on W. 14th Street during a 'Million Hoodie March' in Manhattan on March 21, 2012 in New York City. Thousands of protesters turned out to demonstrate against the killing of the black unarmed teenager by a white neighborhood watch captain. The protesters took to the streets after holding a large rally in Union Square. (Photo by Mario Tama/Getty Images)

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Tracy Martin (L), and Sybrina Fulton, parents of slain teenager Trayvon Martin, address supporters at a Million Hoodies March on March 21, 2012 in New York City. Family members joined hundreds of protesters calling for justice in the killing of Trayvon Martin, 17, who was was pursued and shot on February 26 in Sanford, Florida by 'neighborhood watch' member George Zimmerman, reportedly because the teenager's hoodie made him look suspicious. Under Florida's 'Stand Your Ground' law, Zimmerman has not been charged with a crime in the shooting. (Photo by John Moore/Getty Images)

  • A Million Hoodies March Protests Death Of Trayvon Martin

    NEW YORK, NY - MARCH 21: Sybrina Fulton, mother of slain teenager Trayvon Martin, speaks at the Million Hoodies March on March 21, 2012 in New York City. The family members joined hundreds of protesters calling for justice in the killing of Trayvon Martin, 17, who was was pursued and shot on February 26 in Sanford, Florida by 'neighborhood watch' member George Zimmerman, reportedly because the teenager's hoodie made him look suspicious. Under Florida's 'Stand Your Ground' law, Zimmerman has not been charged with a crime in the shooting. (Photo by John Moore/Getty Images)

  • Federal Government To Investigate Shooting Of Unarmed Teen Trayvon Martin

    MIAMI, FL - MARCH 21: Protesters hold cans of ice tea and Skittles which is what the 17-year-old Trayvon Martin is reported to have been carrying when he was killed by neighborhood watch person, George Zimmerman on February 26 in Sanford, Florida, on March 21, 2012 in Miami, Florida. The Justice Department and the FBI opened an investigation into the death of the black teenager, and the local state attorney announced that he had asked a grand jury to investigate. (Photo by Joe Raedle/Getty Images)

  • Federal Government To Investigate Shooting Of Unarmed Teen Trayvon Martin

    MIAMI, FL - MARCH 21: Protesters hold cans of ice tea and Skittles which is what the 17-year-old Trayvon Martin is reported to have been carrying when he was killed by neighborhood watch person, George Zimmerman on February 26 in Sanford, Florida, on March 21, 2012 in Miami, Florida. The Justice Department and the FBI opened an investigation into the death of the black teenager, and the local state attorney announced that he had asked a grand jury to investigate. (Photo by Joe Raedle/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: A reporter waits to broadcast at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Protesters demonstrate at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: People attend a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Protesters demonstrate at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: A protester holds a sign with pictures of George Zimmerman at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by white and Hispanic neighborhood watch captain George Zimmerman. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Protesters demonstrate at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Protesters demonstrate at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Sanford resident Rodney Stokes carries his son Rodney Stokes Jr. on his shoulder at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Protesters demonstrate at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Protesters demonstrate at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Rev. Al Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Rev. Al Sharpton (R) looks on at a rally with Tracy Martin (R), father of slain teenager Trayvon Martin, on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)

  • Shooting Death Of Unarmed Teen Trayvon Martin Sparks National Outrage

    SANFORD, FL - MARCH 22: Rev. Al Sharpton departs as media are reflected in a vehicle window at a rally for slain teenager Trayvon Martin on March 22, 2012 in Sanford, Florida. Sanford Police Department Chief Bill Lee announced today he will temporarily step down following the killing of the black unarmed teenager by a white and Hispanic neighborhood watch captain. Sharpton organized today's rally. (Photo by Mario Tama/Getty Images)