A suburban sex-trafficking ring involving underage girls led to the conviction Thursday of an Amherst man accused of using threats, intimidation and violence to keep young women and girls working for him.

Kenneth Graham, 25, now faces up to life in prison.

A federal court jury deliberated less than two hours before finding Graham guilty of three sex-trafficking charges, one for each of the victims who testified against him.

The verdict followed several days of emotional and often graphic testimony by the three females and an outright denial by Graham, who also took the stand.

“I told him, ‘I’m 16,’ ” one of the victims, now 18, told the jury earlier this week. “It didn’t seem like it fazed him at all.”

Graham was convicted of running a sex-trafficking operation out of a handful of hotels and motels in Amherst and Cheektowaga before his arrest last August.

During their testimony, the victims said Graham recruited them and then used threats and violence to keep them working long after they wanted out of the business.

Graham countered by suggesting the victims were involved in prostitution long before he entered their lives, a fact two of the victims acknowledged during the trial.

“She was a prostitute when I met her,” Graham said of one of the underage victims. “How could I force her to be a prostitute?”

Graham’s trial before U.S. District Judge Richard J. Arcara provided a glimpse into the world of human trafficking and what experts say is a trend toward more and more domestic incidents of women and children forced into prostitution.

Two of the three victims in the Graham case said they were forced to see up to six or seven men a day at times.

The government’s case against Graham – he was investigated by the Department of Homeland Security – came down in large part to the credibility of the three victims and Graham.

“Our witnesses were incredibly brave,” Assistant U.S. Attorney Robert C. Moscati said in his closing argument. “Who would come in and testify about being a prostitute? Who would do that? Only someone who thought it was important.”

Graham’s defense lawyer used every opportunity to poke holes in the victims’ stories and to point out what he called inconsistencies and discrepancies in their testimony.

He also argued that each of the victims was motivated to lie about her involvement with Graham.

In one case, he said, it was to protect an adult boyfriend who was caught with one of the underage victims at a motel in Amherst and later banned from the motel because of prostitution allegations.

In other cases, he said, it was because the victims had developed a personal relationship with Graham and were jealous of each other.

“These three women had reasons to lie,” said defense attorney Michael S. Deal. “When you aren’t telling the truth, it’s hard to fight for it.”

The trial also included testimony from friends and family of the victims and from law enforcement officials involved in the undercover sting operations that led to Graham’s arrest.

Moscati and Assistant U.S. Attorney Kathleen A. Lynch also produced records indicating Graham rented the victims’ hotel rooms and paid for their online sex ads.

One of the underage victims testified about Graham driving her to and from her Buffalo high school and later, after she turned 17, taking her to get a learner’s permit.

She also told the jury about a violent encounter with Graham – she says he hit in her in the face – and how he also flashed a gun at her.

When Moscati asked how long the beating went on for, she said, “It felt like forever.”

From the outset, Graham acknowledged that, yes, he was a customer of the three victims but, no, he never took part or benefited from their work as prostitutes. He also denied knowing two of the victims were under 18.

Like Graham, Deal acknowledged his client’s sexual relationship with the victims, but suggested it was consensual and not part of a larger scheme to entice them into a world of sex for money.

“This sounds like a bad relationship,” he said of his client’s verbal and physical confrontations with one of the victims. “It’s not an act of coercion or force to get her to engage in acts of prostitution.”

Moscati agreed that Graham’s initial relationship with the victims was consensual but, in fact, part of a larger plan for getting the three victims to work for him.

The jury, as part of the Graham case, will decide whether he should forfeit money he might have made as part of the sex-trafficking operation.

Patricia Calleri, an agent with Homeland Security investigations, estimated that amount at about $171,000.