Berkeley County Prosecuting Attorney Pamela Games-Neely contends Newell used the promise of baseball cards to lure his niece from Pikeside Bowl, where her father was inside bowling with his league.
Michael Newell claims the girl was alive and well when he left her in the bowling alley parking lot after handing her some baseball cards from his car.
Frost was the first witness in the third day of testimony. His testimony focused on Jessica's autopsy results and physical evidence found near where the body was discovered on North Mountain on Sept. 20 and at Michael Newell's home.
Games-Neely entered nearly 100 exhibits, including photographs of evidence, the clothing Jessica was wearing when her body was found and a match to her single sneaker, which FBI agents testified was found near the body in a garbage bag that also contained a bed sheet matching one later found in Michael Newell's home.
Frost, who was on the witness stand most of Wednesday morning, said he concluded that Jessica died from severe blunt force trauma.
Using sketches projected onto a screen, he illustrated why he believes she was hit - or hit against something - several times.
It would take multiple blows coming from different directions to produce the radiating patterns of fracturing he found on Jessica's skull, Frost said.
Frost testified that he found two small, fresh bruises on Jessica's exterior genital organs.
However, evidence indicated that sexual intercourse had not taken place, he testified.
Frost said that because of the bruises' coloring, it was his opinion the injury happened before death, either that day or the day before.
The area is so tender, the bruises could have been caused by something like a hard pinch, he theorized.
Upon cross-examination by defense attorney Aaron Amore, Frost said it was possible the bruises were the result of Jessica being dragged through heavy brush like that found in the wooded area where the body was found.
An FBI agent who said he saw the body in the exact condition it was discovered by local police testified that Jessica's one-piece outfit was pulled up on one side and her underwear was inside out when he examined it on Sept. 21.
Frost said he didn't think the girl could have suffered the linear scrapes found on her chest and abdomen through her clothing.
The linear scrapes would be consistent with Jessica being dragged over underbrush or gravel while she was still alive, he said.
FBI agents and one West Virginia State Police sergeant involved in evidence searches on North Mountain and of Newell's home and car testified Wednesday afternoon.
FBI Special Agent Steve Viglianco testified that he and another agent were scanning the area along Fire Tower Road near where the body was found on the morning of Sept. 21 when they found a garbage bag.
After peering inside and seeing a bed sheet, Viglianco said he marked the area with a flag and left the bag for the special agent in charge of examining potential evidence.
That agent, Thomas S. Flosnik, testified the bag contained a child's sneaker and other items as well as the bed sheet.
The right-foot sneaker was the same size, color and style as the left-foot sneaker found on the girl's body, according to the descriptions given by Frost and police.
Douglas K. Miller, special agent in charge of collecting all evidence from the crime scene, testified that he opened the bag at the state police barracks in Martinsburg and found a bed sheet with a jungle cat print, an empty package of Basic Lights cigarettes, an empty "Moon Glow"-brand condom wrapper, a damp washcloth inside a small Ziploc-style bag and the sneaker.
The items were displayed in court.
According to court records, Michael Newell's fingerprints were found inside the sealed Ziploc-style bag.
FBI agents testified that they found a sheet and comforter with a similar jungle cat print, "Moon Glow"-brand condoms and a Basic Lights carton in a Sept. 22 search of the home Michael Newell shared with his parents and a younger brother.
Only the sheet was displayed in court.
The trial, expected to take two weeks, will resume at 9 a.m. today.
If convicted, Newell could be sentenced to life in prison without mercy.