PASCO COUNTY, Fla. — Curtis Reeves' defense team described the Pasco County Sheriff's Office investigation into the 2014 shooting of 43-year-old Chad Oulson as a “train wreck.”

Wednesday was the eighth day of testimony in the trial.

Reeves, 79, is facing charges of second-degree murder and aggravated battery and could spend the rest of his life in jail if found guilty in the movie theater shooting of Oulson.

Jurors heard Wednesday from a crime scene reconstruction expert who explained some of the do's and don'ts of crime scene investigation.

Dr. Michael Knox didn't directly comment on the work of Pasco investigators, but he gave his take on how law enforcement should handle different situations at crime scenes.

"One of the things you have to do anytime that you're investigating any type of a crime scene is know your limits,” Knox said, stating that could include lack of training or experience.

Last week, Reeves' attorneys questioned the experience of one of the lead investigators.

The detective testified this case was just the second time he was assigned as a crime scene detective, and he hadn't taken a training course on homicide at the time.

Knox said law enforcement should consider outside resources if they don't feel comfortable handling certain cases, especially since a scene can be held as long as needed.

"Once you let it go, it's gone,” he said of crime scenes. "You have to do this stuff, you have to document all these different things, and if it requires getting outside help, that outside help is available."

Knox also told the defense any video should be watched and secured immediately - with a search warrant, if necessary.

Investigators previously testified theater management told them surveillance footage wasn't readily available, and gave them copies later.

“You would not let that just go and then rely on somebody else to provide it, because you don't know what they're going to give you and what's been contaminated in the process,” Knox said.

The defense also brought up a number of times witnesses were allowed to gather in the theater's concession area.

Deputies never tried to separate them or told them not to talk with each other after the shooting.

Knox said when witnesses congregate, that can contaminate their observations. He called separating witnesses a "day one concept" in law enforcement training.

The theater witnesses jurors heard from so far said they didn't talk to each other after the shooting.

As for the crime scene detective, he told the court he'd been in law enforcement for nearly 15 years at the time of the shooting.

He also said he had responded to homicide scenes before.

Spectrum Bay News 9 reporter Sarah Blazonis is covering the trial. Follow her on Twitter or by using the Live Updates feed below.