(NewsNation) — Defense attorneys in South Carolina attorney Alex Murdaugh’s double murder trial continued Monday to question the way state agents collected and analyzed evidence in the shooting deaths of Murdaugh’s wife and son.

Over the first three days of testimony, prosecutors have mostly called officers and crime scene technicians to present evidence to the jury that investigators will likely later explain in more detail. They described their case as a puzzle in last week’s opening statement.

While cross-examining witnesses, though, defense attorneys have asked questions suggesting the metaphorical puzzle pieces either aren’t clear or prosecutors aren’t putting them all on the table.

NewsNation will stream the trial. You can watch it on this page when it begins at 9 a.m. ET.

Murdaugh, 54, is standing trial on two counts of murder in the shootings of his wife and son at their Colleton County home and hunting lodge on June 7, 2021. His wife, Maggie, 52, was shot several times with a rifle; their son Paul, 22, was shot twice with a shotgun near kennels on the property. Murdaugh faces 30 years to life in prison if convicted.

State Law Enforcement Division Special Agent Melinda Worley testified for hours Friday for the prosecution about evidence collected, including photographs of the bodies, shotgun pellets and DNA swabs from the scene, clothes and fingernail clippings from the autopsies and other items.

In Monday’s cross-examination, defense attorney Dick Harpootlian honed in on several items, including identifying footprints, one of Worley’s specialties. She told him one of the footprints in blood near where Murdaugh’s son was shot came from a deputy.

“Is that the preservation of the scene that your standards require?” Harpootlian asked.

“Not exactly, no,” Worley responded.

Harpootlian also had Worley come off the stand and work on a rough diagram of the angles of the shots fired at Paul and Maggie Murdaugh, pointing out a significant disparity between the directions the shots at each victim came from.

Worley said that can happen when a shooter is moving.

“One explanation would be movement. One explanation would be two shooters,” Harpootlian said.

The defense attorney also pointed out a few mistakes in Worley’s work. For instance, Worley had examined a shotgun that Alex Murdaugh said he’d grabbed to possibly defend himself after finding his wife and son. Harpootlian said the special agent incorrectly determined that the shells inside the shotgun were the same size, when, in fact, they were different sizes. The defense attorney also noted that the angle of a gunshot was given in different degrees in Worley’s scene notes and her final report.

South Carolina Attorney General Alan Wilson sat behind his prosecutors on Monday, his first appearance during the trial.

Alex Murdaugh continued to rock and dab his eyes during more graphic testimony, including when Harpootlian showed a photo of his wife’s body to ask Worley if there could have been a shoeprint on his wife’s calf that was not formally documented as the scene was examined.

Worley said she couldn’t be certain.

Later Monday morning, another state agent testified about the timing of phone calls and texts from a friend of Paul Murdaugh. Earlier evidence has suggested that Alex Murdaugh, his wife and son were all by the kennels about four minutes before the victims stopped using their cellphones. Cellphone data shows Alex Murdaugh left the area to visit his ailing mother about 20 minutes later.

Senior Special Agent Jeff Croft testified about guns, ammunition, and fired casings gathered from the Murdaugh home after the killings, showing at least four different shotguns and rifles to the jury and testifying that the Murdaughs kept the weapons loaded in their gun room.

Prosecutors in their opening statement said the guns that killed Paul and Maggie Murdaugh have not been found, but markings on casings found around the home that may have been used for target practice matched casings found at the scene.

Alex Murdaugh has pleaded not guilty to the murders and, if convicted, faces life in prison.

The trial is expected to last another two weeks.