Public Safety

Man accused of killing Mollie Tibbetts wants to hire 2 more experts at public expense

Defense: Experts needed to testify about sleep deprivation and DNA

Cristhian Bahena Rivera, 24, is escorted out of the courtroom after pleading not guilty to the charge of first-degree mu
Cristhian Bahena Rivera, 24, is escorted out of the courtroom after pleading not guilty to the charge of first-degree murder in the death of Mollie Tibbetts on Wednesday, Sept. 19, 2018, at the Poweshiek County Courthouse in Montezuma. (Pool photo, Kelsey/Kremer, The Gazette)

The man accused of killing Mollie Tibbetts last year plans to hire two more expert witnesses, at the public’s expense, to testify about sleep deprivation and DNA analysis.

Attorneys for Cristhian Bahena Rivera, 24, charged with first-degree murder, in a motion filed late Wednesday said retainers of $2,500 and charges of $300 per hour are needed for Kimberly Fenn, an associate psychology professor at Michigan State University. She will testify about sleep deprivation and how it might affect a person’s voluntary actions and statements if in “sleep deprived state.”

The defense previously has made arguments that Bahena Rivera’s statements to law enforcement weren’t voluntary, nor was his waiver of Miranda rights. The defense will ask the court next week to not allow his statements to police be used at trial.

Lawyers Chad and Jennifer Frese, in the motion, said Brian Leslie, another expert previously retained in the case, can testify about sleep deprivation and its role in interrogation techniques and whether the statements made by Bahena Rivera were voluntary. But he can’t offer an analysis on sleep deprivation’s effects on a person’s judgment, as Fenn could.

The other expert, Dr. Michael Spence, a forensic DNA consultant with Spence Forensic Resources in Las Cruces, N.M., requires a $3,000 retainer and charges $300 per hour, according to the motion. The retainer should be sufficient for now to review and consult with Bahena Rivera and provide testimony about DNA analysis, the motion says.

“Should this matter proceed to trial and Dr. Spence’s testimony be required, an additional stipend would be necessary,” the motion states.

The lawyers also are asking that an interpreter, Sara Gardner, who is certified in Missouri, be appointed so she can continue providing services to the defendant. The state public defender and state court administration don’t want to pay her as an interpreter because she’s not on the Iowa courts roster.


The lawyers argue Gardner is providing expert witness services, according to the motion. She was needed to translate the interview of Bahena Rivera so the defense could challenge the accuracy of the Spanish used by law enforcement and the translated transcript provided by the prosecution.

The defense is asking the court to recognize her as an expert and allow her to continue.

Authorities said Bahena Rivera admitted to killing 20-year-old Tibbetts, then led them to a cornfield south of Guernsey on Aug. 21, 2018, where the University of Iowa student’s body was hidden. Tibbetts had been missing for about a month after she went missing while jogging in Brooklyn, Iowa.

An autopsy showed she died of stab wounds.

An evidence suppression hearing is set for Tuesday and Wednesday in Poweshiek County District Court.

Bahena Rivera’s trial was reset last week to Feb. 4 in Woodbury County. The trial was moved because the defense argued the extensive pretrial publicity would prevent the undocumented immigrant from having a fair trial.

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