Rivera trial: Prosecution rests its case, defense denied acquittal

During the sixth day of the trial for Cristhian Bahena Rivera, the prosecution rested its case, finishing witness testimonies on Monday.


Kelsey Kremer

Iowa State Medical Examiner Dr. Dennis Klein answers questions from the witness stand during Cristhian Bahena Rivera’s trial, on Monday, May 24, 2021, in the Scott County Courthouse, in Davenport, Iowa. Bahena Rivera is on trial after being charged with first-degree murder in the death of Mollie Tibbetts in July 2018. (Pool Photo/Kelsey Kremer/Des Moines Register)

Rachel Schilke, Summer Editor

The defense’s request for acquittal was denied during the trial for Cristhian Bahena Rivera on Monday.

Bahena Rivera is charged with first-degree murder in connection to the disappearance and death of University of Iowa student Mollie Tibbetts. If convicted, he will serve life in prison.

After the prosecution rested its case, defense attorney Jennifer Frese asked that Judge Joel Yates dismiss the case, stating that the prosecution did not prove intent to kill or other elements of first-degree murder. 

She added that the prosecution also did not prove second-degree murder, which has the element of “malice aforethought.”

Brown said given the admission Bahena Rivera gave to authorities, the nature of injuries, and the presence of blood in Bahena Rivera’s trunk, he believes the prosecution provided more than enough evidence.

“It is our opinion that the evidence here is overwhelming concerning the guilt of the defendant on a first-degree murder charge,” Brown said. “There is evidence of injury, there’s evidence of identity, there’s evidence of specific intent.”

After hearing both sides’ arguments, Yates denied the motion for acquittal, stating that within the confines of the law, the state provided evidence that could prove first-degree murder.

The trial will continue on Tuesday at 8:30 a.m. It is unclear whether the defense will call Bahena Rivera to testify at this time, a decision that defense attorney Chad Frese called “difficult” during jury selection on May 17 and 18. 

Monday marked the sixth day of the trial, and day four of witness testimonies and presentation of evidence. Agent Trent Vileta from DCI, FBI Supervisory Special Agent Kevin Horan, State Medical Examiner Dennis Klein, and Heather Garvin took the stand on Monday, bringing the total number of witnesses to 18.

Trent Vileta

Agent Trent Vileta, who works on new and cold-case homicides for the Iowa Division of Criminal Investigation, was the case agent assigned to Tibbetts’ disappearance when it was originally a missing person’s case.

Vileta said to start, he interviewed those closest to Tibbetts. He said Tibbetts was an extremely low-risk missing person at the time due to her lifestyle and relationships.

“We read some of the nicest text messages,” he said. “It was hard to find anything negative about Mollie Tibbetts.”

He said agents spent approximately 30 days in the search for Tibbetts before her body was found on August 21, 2018. 

Judge Joel Yates called for a recess during Vileta’s testimony just 15 minutes after it began because of technical difficulties with the sound system. Reports from within the courtroom said the jury was having a hard time hearing Vileta’s testimony.

After stepping back on the stand, Vileta said the DCI utilized services from the Iowa Department of Public Safety, Poweshiek County Sheriff’s Office, patrol DCI, narcotics and fire marshals, and the FBI. 

“It was a community effort from day one,” Vileta said. “We had airplanes flying over, we got calls from hospital helicopters saying, ‘We have extra fuel’…We didn’t necessarily care who found her.”

He said Dalton Jack, Tibbetts’ boyfriend who testified on May 19, was interviewed on multiple occasions. Jack was eliminated as a suspect as no witnesses came forward with information that he was in Brooklyn, Iowa, on July 18, 2018.

Vileta said he did not run across Bahena Rivera’s name and information on the black Chevy Malibu – the vehicle seen in video surveillance where Tibbetts was seen jogging – until August 2018. 

When authorities viewed surveillance owned by Logan Collins, who testified on May 20, they saw the black Chevy Malibu and began attempting to locate it, Vileta said.

“The footage on Logan Collins cameras broke open the case for us,” he said. “It was the lead we needed. It provided not only the black Malibu, but it also had a very brief glimpse of Mollie Tibbetts jogging.”

He said Steve Kivi, who testified on May 20, located the vehicle and identified Bahena Rivera as the driver on August 16, but authorities did not make contact with the defendant until August 20. Vileta said Wisconsin had a missing person’s case as well, so the investigators lost many FBI resources.

Vileta said investigators made it a priority to request law enforcement officers that could understand and speak Spanish well when authorities made the decision to visit Yarrabee Farms, where Bahena Rivera worked.

Prosecutor Scott Brown asked Vileta why authorities spoke to all of the employees at Yarrabee Farms. Vileta testified that, in 2018, the political environment was hostile toward immigrant communities.

“We were concerned that any contact that our immigrants would have with the police or anybody from the government would cause them fear, or maybe cause them to flee or not cooperate,” Vileta said. “We were trying to take every effort possible to make them feel comfortable with us but we also wanted to be sure we could identify them.”

He added during cross-examination that DNA was taken from the employees purely for identification purposes in the chance that they left and began working under false names and paperwork.

Vileta did not participate in the interviews of Bahena Rivera or Yarrabee Farms’ employees. He testified he was there when Tibbetts’ body was found on August 21, 2018. He did not locate Tibbetts’ FitBit or cell phone. Authorities could not locate the murder weapon either, he testified.

Chad Frese spent considerable time during cross-examination on Vileta’s investigation of other suspects.

He asked Vileta about Jack being a suspect and his whereabouts on July 18. Vileta testified among other evidence, Jack’s roommate vouched that he was in the hotel room in Dubuque, Iowa, on the night of July 18. 

Frese asked Vileta whether or not Jack’s anger problems would have been something he wanted to know, to which Vileta said knowing about Dalton’s anger issues is key in victimology.

Victimology is defined as the study of the relationship between the victim and individuals around them, including the offender, friends, and family. Authorities use this to determine if the victim knew the offender.

Frese focused on Ron Peksa – who has a known history of violence against women and was an initial suspect– as his house is a quarter-mile from where the body was found. Vileta said authorities did not talk to Peksa after Tibbetts’ body was found, despite receiving two tips about Peksa.

Vileta testified that in a report, it was written that Peksa had a “torture room” in his basement. However, he said after doing a walkthrough of the house, Vileta did not find a room to that effect.

When asked about Jackson Eichhorn, another suspect, Vileta said Google put Eichhorn’s phone in the area at a cemetery at the time of her disappearance. After interviewing him, Vileta said authorities ruled out Eichhorn as a suspect.

Vileta said he got a lead on Michael Scott, another suspect whose car broke down during his travel through Brooklyn, Iowa. He testified that Scott left his car, bought a new one, and continued driving, which he said was unusual. 

Frese said a brown hair was found in Scott’s ditched vehicle, but Vileta testified that Scott was ruled out as a suspect. The instances regarding the rule out were not specified.

When asked about the end of the investigation, Vileta testified that the purpose for looking for DNA and presence of Tibbetts’ blood was to corroborate statements made by Bahena Rivera. 

He added that no DNA from Bahena Rivera was found on Tibbetts’ body, as her body was decomposed.

Kevin Horan

Kevin Horan, special agent with the FBI, has expertise in the analysis of cell records. He is part of the original nine members of the FBI’s Cellular Analysis Survey Team, which specializes in cellular telecommunications and analysis.

Horan said he was provided with all of Tibbetts’ cell records including voice calls and text messages. He was asked to review the time Tibbetts was jogging on July 18, 2018. Between 8:15 p.m. and 8:28 p.m. Tibbetts’ cell phone number connected to a Sprint cell site tower. 

As previously reported by The Daily Iowan, Tibbetts is suspected of disappearing between 8:20 p.m. and 8:30 p.m.

“What [the cell map] is telling me is that, at least in reference to this tower in this sector, that the phone is somewhere, really anywhere, in Brooklyn to the east because it’s communicating with the northeast side of the tower,” Horan said. “It’s not on the west, it’s not on the south. If this was all I had, I would not be able to tell much about the location of her phone.”

Horan said they added in the per call measurement data that provided the time Tibbetts’ phone would have connected to the tower. He said after looking at this data, he determined Tibbetts’ phone was moving in an easterly direction from 8:15 p.m. to 8:28 p.m.

He added that Tibbetts’ phone typically would upload a map to FitBit showing her running route. However, on July 18, no map was uploaded, so FitBit was unable to provide her route that night. 

Horan said he then referenced prior routes and determined it is likely she was running a 10-minute mile on the same route she had run previously.

He said at 8:35 p.m. the phone pinged from an area much farther than where it was at around 8:28 p.m., traveling at about 60 miles per hour. 

Dennis Klein

Dennis Klein, the state medical examiner, performed the autopsy and examination of Tibbetts’ body. He was called to the cornfield where the body was found on August 21, 2018.

He concluded after an autopsy that Tibbetts died of multiple sharp force injuries and ruled her death a homicide. He said all the injuries are consistent with the same weapon but cannot rule out other weapons.

He said because of the weather conditions in July 2018, Tibbetts’ body was in a state of rapid acceleration of decomposition. Klein categorized the body as moderate to severe decomposition with skeletonization, meaning parts of the bones were starting to show through.

Klein said he and a team of technicians assisting during the autopsy were unable to recover any blood because of the state of decomposition. The autopsy took place on August 22, 2018.

He said the autopsy was done in various stages, with the examination taking around three hours. The team documented findings, including taking photographs, taking notes, and observing. 

Afterwards, Klein said they took X-rays of the body to see if there were any retained fragments that would help explain the cause of death. He testified that there were no fragments found in the body.

During his testimony, Klein described all of the injuries to the jury in collaboration with photographs.

He found nine definitive stab wounds, corroborated by defects to the bone or defects to clothing, and suspects there were up to 12 wounds. Some wounds were not labeled definitively because of decomposition and the state of soft tissue.

The weapon used was a single-edge blade that had both a blunt and sharp end. The blade was strong enough to penetrate the skull, Klein testified. Two wounds were found on the skill, with one penetrating the skull and the other a wound near Tibbetts’ cheek.

After an observation by forensic anthropologist Heather Garvin, additional sharp force defects were identified in the cervical vertebra, which are the bones that stack to form the neck. It was determined there were several arteries and veins in the neck that could have been penetrated by the weapon, Klein said.

Klein testified that he was unable to determine the amount of force put behind the blade, but that the amount of force depends on how sharp the blade is and the tissue it is going through.

Defects on Tibbetts’ pink sports bra, which was one of three articles of clothing on the body when it was found, were consistent with stab wounds going through the bra and into the body, Klein said.

During cross-examination, Klein said he was unable to determine the vantage point of the assailant, Tibbetts’ vantage point, the size of the assailant, and the order of the wounds.

Heather Garvin

Heather Garvin, a forensic anthropologist, assisted Klein in examining Tibbetts’ body during the autopsy. She was present at the beginning to see the condition of the remain and create a plan with Klein to review the bones

A forensic anthropologist applies specialized knowledge about human skeletal anatomy to provide information about the identity or cause of death. 

Garvin said the bones were prepared for her examination through a process called maturation, which places bones in a heated water bath to remove soft tissue.

She said she spent at least 20 hours looking at the remains, and spent 10 to 20 hours preparing her report for Klein. She said she received an almost complete skeleton, missing a tooth, neck bone, and toe bone because of decomposition and exposure to the elements.

Overall, Garvin determined a minimum of seven impacts: the head, right side of neck, left side of neck, right sixth rib, left sixth rib, left seventh rib, and left eighth rib. 

Photographs of Tibbetts’ skull showed a penetration wound going through the skull. Gavin said the knife went through a few millimeters of bone that covers the brain, but could not indicate whether or not it hit any other surfaces.

She said although there were four separate defects to the right side of the neck bone, they could have been created with a single impact. She said all she could say was that there was a minimum of one stab wound to the right side of the neck and a minimum of one stab wound to the left, as well.

Wounds to both sides of the neck could have been created with a slashing motion either by a perpendicular impact or side impact of the blade, Garvin testified.

There were several slash marks on the ribs, she said. On the right sixth rib, shown to the jury, the points were V-shaped and had three deeper sharp force defects and a couple shallow, linear defects, as well.

She said given the close proximity of the defects on the right sixth rib, she reported that there was a minimum of one impact to the area.

Photographs of the left sixth rib indicated two sharp force defects. Garvin testified that the injuries appear to be more of a scrapping injury compared to the deep notches in previous photographs.

The left seventh rib showed a sharp force defect on the outer surface of the rib, while the others were on the top part of the rib, Garvin said. There was a linear, perpendicular notch and a trailing scratch from that present, she said.

On the left eighth rib, Garvin said there were defects consistent with sharp force trauma, as if bone was cut away or carved out from that impact. She concluded a minimum of one impact on that rib, she testified.

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