LOS ANGELES — Three Philippine nationals caught in a sting operation in their native country were convicted Monday of importing military-grade weapons to the United States in a case that earned international attention last year because of a defense lawyer's contention that an undercover FBI agent spent U.S. taxpayer dollars on prostitutes.

After a four-week trial, a federal jury in Los Angeles convicted Sergio Syjuco, 26, Cesar Ubaldo, 27, and Arjyl Revereza, 26, of conspiring to illegally import the weapons and aiding and abetting their importation to the U.S.

Each of the men could be sentenced to more than 20 years in prison and fined $1 million or more. They're scheduled to be sentenced June 9.

In late 2010, Ubaldo began meeting an FBI agent who was posing as a prospective buyer of high-powered weapons for U.S. and Mexican drug cartels, according to evidence presented at trial.

Prosecutors said Ubaldo introduced the agent to Syjuco, who supplied the weapons, and Revereza, an officer in the Philippines Bureau of Customs who facilitated the movement of the weapons between the Philippines and the U.S.

The men were indicted after authorities seized weapons at the Port of Long Beach in California in June 2011. The weapons seized included a grenade launcher, a mortar launcher and 12 machine guns.

Before the trial began, Syjuco's attorney John Littrell alleged that the undercover FBI agent spent U.S. taxpayer dollars on prostitutes in the Philippines for himself and others during the investigation, and asked that the charges be thrown out because of the misconduct. The motion was denied.

Prosecutors acknowledged the agent sought nearly $15,000 in reimbursements for "entertainment" and other expenses.

But Littrell said in court documents that two clubs where the men met were suspected brothels, one of which was raided in May by Philippine authorities, with dozens of victims of sex trafficking rescued, some of them under-aged girls.

The agent, whose name was not made public, vehemently denied this, saying he never paid to have sex or knowingly paid a bill that included prostitution.

Bill Lewis, assistant director in charge of the FBI's Los Angeles office, said in a statement Monday that the verdict vindicated the agent's work.

"The undercover case agent assigned to this investigation and his family endured true hardship during this lengthy trial, during which he was accused of unfounded illegal activity," Lewis said. "It's clear the jury weighed the evidence in reaching a guilty verdict, and not theories put forth by the defense."

Also on HuffPost:

Loading Slideshow...
  • Christie Harris

    This Oklahoma woman was sentenced to 25 years after smuggling not only meth in her butt, but also a gun in her vagina. <a href="http://www.huffingtonpost.com/2013/07/10/christie-harris-hid-gun-in-vagina-meth-in-butt-sentenced_n_3574436.html" target="_blank">Read the whole story here. </a>

  • Alexis Clancy

    This Florida woman was allegedly caught with a hypodermic needle stowed away in her anus. <a href="http://www.huffingtonpost.com/2013/03/01/alexis-clancey-hides-needle-in-butt_n_2789700.html?utm_hp_ref=weird-news&ir=Weird%20News">Read the whole story here. </a>

  • Cocaine Diapers

    Priscilla Pena and Michelle Blassingale were arrested at JFK Airport after arriving from the Dominican Republic in late January. Drug-sniffing dogs allegedly detected something. Authorities said Pena had seven kilos of cocaine in silver plastic, wrapped around her butt like a disposable diaper.

  • Rasoul Speight

    Rasoul Speight, 32, is facing a narcotics charge after New Jersey cops yesterday discovered a whopping 100 bags of heroin hidden in his anus.

  • Ashley Bellamy

    Bellamy allegedly hid 36 vials of crack cocaine in her vagina to stay out of police custody. But officers noticed that the Philadelphia woman was walking funny, and she admitted to her hiding place. "The woman says, 'I have crack up in my vagina,' and she pushed out 36 vials of crack cocaine that were in a bag," Upper Darby Police Superintendent Michael Chitwood said. "Thank God the lady didn't have a snake or a crocodile, or we'd really have been in trouble."

  • Pot Found In Frozen Carrots

    42 packages of marijuana were found stashed inside boxes of carrots on the back of a truck trying to pass through the Otay Mesa cargo facility.

  • Crack, Pot Found In Man's Prosthetic Leg

    Jose Santiago is accused of hiding 2.5 grams of crack cocaine and 2.8 grams of marijuana inside his prosthetic leg.

  • Kiana Howell and Makeeba Grahama

    Kiana Howell (L) and Makeeba Graham (R) are accused of attempting to smuggle cocaine from Guyana into the U.S. in their hair.

  • Byron Harvey

    Harvey is accused of stuffing clothes shoes and a watch worth a combined $450 <a href="http://blogs.tcpalm.com/off_the_beat_will_greenlee_blog/2012/09/byron-harvey-apparently-had-a.html" target="_hplink">in his pants.</a> He also allegedly had several pills stuffed in his pants that he claimed were not his.

  • Cocaine Bricks In XBox

    Carlos Valenzuela, 42, was pulled over by El Paso authorities for a traffic violation, but the routine stop led to the discovery of <a href="http://www.huffingtonpost.com/2012/05/07/cocaine-in-xbox-carlos-valenzuela_n_1495223.html#s=946270" target="_hplink">two large bricks of cocaine inside an XBox 360.</a>

  • Man Allegedly Ties 89 Bags Of Drugs To Penis

    A traffic violation by Ray Woods, 23, caught the attention of Pennsylvania police, who then discovered Woods was packing something quite large: <a href="http://www.huffingtonpost.com/2012/04/12/89-bags-of-heroin-tied-to-penis_n_1420733.html" target="_hplink">89 bags of heroin and cocaine tied to his penis.</a>

  • Cocaine Found In Tampon Box

    Cindy Davidson of Salt Lake City found quite a surprise when she opened a box of tampons she purchased: <a href="http://www.huffingtonpost.com/2012/05/04/cocaine-tampons-accidenta_n_1477321.html" target="_hplink">cocaine wrapped in cellophane.</a>

  • Crack Found In Suspect's Butt

    Florida police not afraid to get their hands dirty <a href="http://www.huffingtonpost.com/2012/02/17/police-find-crack-in-butt_n_1285604.html" target="_hplink">discovered crack in the butt</a> of 28-year-old Ramon Blair.

  • Idaho Mechanic Finds $40,000 Of Cocaine In 82-Year-Old Woman's Car

    An Idaho mechanic <a href="http://www.huffingtonpost.com/2012/05/10/idaho-mechanic-discovers-cocaine_n_1506071.html?ref=drugs" target="_hplink">found 1.16 pounds of cocaine</a> -- that's more than $40,000 worth on the street -- inside the engine compartment of a car belonging to an 82-year-old woman.