The lead agent who investigated the disappearance and murder of University of Iowa student Mollie Tibbetts testified Tuesday that there was no doubt in his mind who killed her.

“Cristhian Rivera murdered Mollie Tibbetts,” special agent Trent Vileta said in court.

Vileta rejected a theory by Cristhian Bahena Rivera’s attorneys that he was framed for Tibbetts’ kidnapping and murder as part of a sex trafficking ring. The attorneys claim the alleged sex trafficking ring was investigated and that resulting evidence was withheld from them by law enforcement authorities.

“I don’t remember any tips that she (Tibbetts) was the victim of sex trafficking, but I didn’t see all of them either,” Vileta said.

A jury convicted 27-year-old Bahena Rivera in May of first-degree murder, but his sentencing was postponed after his attorneys requested a new trial in order to be allowed to review evidence in any ongoing investigations into sex trafficking in and around Poweshiek County, Iowa, where Tibbetts went missing in July 2018. Her body was discovered in an Iowa cornfield about a month after she vanished.

During Tuesday’s hearing, which lasted more than four hours, Bahena Rivera’s attorneys called Arne Maki to testify about a conversation he said he had in July 2020 with a 21-year-old inmate while they were both being held at the jail in Keokuk County, Iowa.

Maki, 46, who is now serving a prison sentence for domestic violence, claimed the inmate who he befriended told him that he and another man killed Tibbetts on the orders of a sex trafficker after she was kidnapped and brought to a sex trafficking “trap house.”

“He’s like, ‘yeah, I killed her,'” Maki testified about the inmate who defense attorneys named in court documents and during the hearing. “I’m like, ‘I don’t believe you.'”

Maki claimed the man then mentioned Bahena Rivera, a Mexican national who was in the country illegally and working at a dairy in Poweshiek County when he was arrested and charged with Tibbetts’ killing.

“He’s like, ‘We set him up.’ He’s like, ‘It’s a sex trafficking case gone wrong, and I stabbed her to death and put her in a tarp, me and my Black friend that don’t speak English good.'”

Maki testified that he doubted the inmate’s story until he saw TV news reports on Bahena Rivera’s testimony during his trial.

Bahena Rivera claimed he was kidnapped at his home near Brooklyn, Iowa, by two armed masked men, who ordered him to drive to where Tibbetts was expected to be jogging. He claimed that when they found Tibbetts, one of the men stabbed her to death, put her body in the trunk of Bahena Rivera’s car and made him drive to a cornfield, where the young woman’s badly decomposed remains were discovered a month after she went missing.

Bahena Rivera said that while he placed Tibbetts’ body in the cornfield, he did not kill her.

“Right there my conscience told me that I should say something, even if it’s not true,” Maki said, explaining why he told authorities about the inmate’s purported confession.

But under cross-examination from prosecutor Bart Klaver, Maki said he did not know that the inmate who confessed to him was in a rehab facility under court supervision at the time Tibbetts disappeared.

Judge Joel Yates, who presided over Bahena Rivera’s trial, told the attorneys he will make a written decision as soon possible on the defense motion for a new trial.

Earlier this month, Yates rejected the motion to allow Bahena Rivera’s attorneys an opportunity to review evidence in ongoing sex trafficking investigations in Poweshiek County and in the case of a missing 11-year-old boy, Xavior Harrelson, who vanished in May from his home in Poweshiek County. The defense attorneys suggested that the man who they allege operated the sex trafficking “trap house” once had been the boyfriend of Harrelson’s mother.