Jessica Juarez first took the stand, testifying as an expert in forensic anthropology. Juarez worked at Western Michigan University Homer Stryker M.D. School of Medicine (WMed) in Kalamazoo, where she gained extensive experience in comparative medical radiography – the process of comparing radiographs, or X-rays, taken before death with those taken after death.

Through this process, forensic anthropologists examine the unique shapes and structural features of bones visible in the radiographs.

By comparing antemortem X-rays of a known individual with postmortem images of unknown remains, the anthropologist can determine whether the skeletal characteristics are consistent with the known person’s X-rays and confirm an identification.

Juarez testified that WMed requested antemortem scans of Harley Corwin from OSF St. Francis Hospital & Medical Group in Escanaba. The school received a CT scan taken during Corwin’s treatment at the hospital at some point in time.

Harley Corwin and Tavaris Jackson's cellphone data were analyzed and presented to the jury in Jackson's murder trial on Monday. (Sophie Vogelmann | Daily Press)

WMed later performed postmortem X-rays of the recovered remains, Juarez said, positioning the body as closely as possible to the orientation used in the antemortem imaging to ensure an accurate comparison.

Juarez compared Corwin’s antemortem CT scan with the postmortem X-rays taken at WMed, focusing on the shape and structure of the frontal sinus – an anatomical feature that scientific literature has shown can be used as a reliable point of comparison, according to Juarez.

Based on this comparison, Juarez concluded that the anatomical features were consistent and positively identified the remains as Corwin.

Later Monday, Parker DeGroot, an analyst with the Michigan State Police, testified as an expert in intelligence analysis and cellphone data interpretation.

DeGroot said he was contacted by another regional analyst who was working to establish a timeline in the case. He compiled and analyzed phone and application data – including Verizon and AT&T records as well as Snapchat and Life360 information – to map the movements of both Corwin’s and Jackson’s phones.

According to his presentation, the data showed Corwin’s phone traveling between her residence, Chloe Benavides’ residence, Jackson’s residence and Ludington Park on July 3.

The data specifically placed Corwin’s phone in the exact parking space at Ludington Park where her vehicle was later captured on a patrol dash camera.

Location data also showed Corwin’s phone leaving The Store Gas Station and traveling southbound past Fuller Park, where a phone call was placed. The device then turned around and returned to the park, with location data placing it near the area where Corwin’s body was eventually discovered.

DeGroot testified that phone data for Jackson was consistent with being in the same area during that time frame.

Further analysis showed Corwin’s phone traveled northbound toward Escanaba alongside Jackson’s phone, including locations near Menards and Walmart

According to previous testimony from Mark Hanson, a former detective sergeant with the Delta County Sheriff’s Office, investigators obtained surveillance video from July 3 showing Jackson at both stores.

The analysis also showed overlapping coverage between Jackson’s and Corwin’s cellphone records on July 4 and July 5. DeGroot said he reviewed Snapchat exchanges sent from Corwin’s Snapchat account to Benavides during this time frame, which he described as “long, kind of rambling messages about the relationships between the victim, the defendant and Chloe.”

Jackson faces one count of open murder – a felony punishable by up to life in prison – in the death of his ex-girlfriend, 22-year-old Harley Corwin. Her body was discovered on July 8, 2023, across from Fuller Park in Ford River Township.

Jackson is also charged with one count of possession of a firearm during the commission of a felony, a two-year felony, and one count of assault resulting in the death of a fetus, also punishable by up to life imprisonment.

He remains lodged in the Delta County Jail.

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Sophie Vogelmann can be reached at 906-786-2021 or svogelmann@dailypress.net.