Witness testimony in Dominic Johnson's murder trial is over.

Defense attorney Lyle Stohler rested his case after calling one witness: Amy Hansen.

Hansen is an investigator with the Office of Public Advocacy who's been working with Stohler for 10 years. She's been in court for the entire trial.

Stohler asked her to drive Knik River Road with an iPhone with AT&T coverage to see what kind of service she had, then testify to the findings.

Location Data Objections

Stohler has repeatedly objected to evidence involving data collected from Johnson's cell phone and devices from the other suspects involved in the case.

Johnson is one of four people accused of beating and killing 16-year-old David Grunwald on Nov. 13, 2016.

Over the past four weeks, state prosecutors brought in several investigators to testify about the cell phone evidence, including location data that places Johnson's phone in the Butte area the night Grunwald was killed.

Johnson led investigators to Grunwald's body in the woods off mile 7 of Knik River Road on Dec. 2, 2016.

Stohler has argued there are no location points that place Johnson on Knik River Road in the area where Grunwald died.

On Tuesday, Alaska State Trooper Ramin Dunford with the technical crimes unit, testified that the closest tower to Knik River Road is blocked by an obstruction. There are several towers that are farther away, but up higher on Clark-Wolverine Road that would be able to provide coverage for the Knik River Road area.

Those towers picked up Johnson's phone at 9:05 p.m. There was no activity on Johnson's phone until 9:35 p.m. when the towers picked up a data connection.

"So that phone could have been on Knik River Road at 9:35?" Assistant District Attorney Melissa Wininger-Howard asked.

"That's correct," Dunford responded.

Johnson's phone was later picked up on cell towers heading back into Palmer around 9:45 p.m.

Cell Service "Experiment"

While Stohler didn't specifically address why he asked Hansen to drive the road looking for service, it appeared he was trying to prove there is cell phone coverage on a good portion of Knik River Road, and therefore Johnson's phone would have hit off closer cell towers if he was in the Bronco the teens drove to the site where Grunwald was killed.

Just minutes into Hansen's testimony, Palmer District Attorney Roman Kalytiak objected.

"What does service mean? Did she try to call? Or is she relying on bars to determine if there's service?" Kalytiak asked.

Hansen explained she relied on the "bars" on the phone to tell her if she had service.

She tried to make one phone call at mile 3 on Knik River Road where she lost service briefly. She did not try to call or text anyone at any other point along the drive. Service also dropped from mile 6 to 7, she said.

"If you're doing this experiment, why didn't you make a number of phone calls? If you're really trying to determine if you have service or reception, why didn't you make a few phone calls?" Kalytiak asked.

"I don't have an answer for you," Hansen said.

Less than five minutes into her testimony, Hansen admitted she didn't know what version of the iPhone she had used.
The jury was excused while the defense looked for the answer.

Just seconds after the jury left, Stohler said it was an iPhone 7s Plus. In November 2016, Johnson was using an iPhone 6 Plus.

Kalytiak made the point the phones were different and cell tower technology could have improved over the past two years.

Hansen took a 19-minute video that showed the various degrees of AT&T service on the phone in relation to where she was driving.

After that was played for the jury, Kalytiak hammered her with questions.

"What are you basing your assumption on if there's one bar on AT&T that that equals service and reception?" Kalytiak asked.

"That's just what I said," Hansen responded.

"You're the one saying it, indicating that we have service for sure if there's one bar on my phone. How do you really know that?" he asked. "You're a GCI user, right? Have you had AT&T ever?"

"No," Hansen said.

"How do you know this is an absolute whenever you have one bar on AT&T you have service and you have reception?" Kalytiak asked.

"Well, I'm not an expert," Hansen laughed quietly.

Kalytiak asked her if she know what the bars meant on a cell phone and if she did any research about the difference between the iPhone versions or information about cell phone tower upgrades in the Butte area.

Hansen repeatedly told him she did not do any research because she was not asked to do so.

"But you could have done that research," Kaytiak said. Hansen did not respond.

Johnson did not testify as his trial.

Closing arguments are scheduled for Wednesday, Dec. 26.

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