TULSA, Oklahoma - The defense in the trial for Tulsa Police Officer Betty Shelby began presenting its case just before lunchtime on Friday.

The defense's fourth witness of the day was Tulsa County Sheriff's Office Corporal Marshal Eldridge.

Eldridge not only trained Shelby when she worked for the sheriff's office, he was also the teacher of Shelby's Drug Recognition Expert course.

Eldridge made a point to say that only one percent of officers in the entire country are DREs. He also said he's "never once found her (Shelby) to not handle stress very well."

However, when the prosecution cross-examined, it asked Eldridge to tell the jury about a specific incident during the DRE that upset Shelby.

Special Coverage: Betty Shelby Trial

Eldridge said they gave pop quizzes regularly throughout the course.  That particular day, Shelby got a zero on the quiz. Eldridge described Shelby's reaction to this score as "vocal."

He said she screamed, yelled, teared up and then stormed out of the room and into the bathroom. Shelby did come back later and apologize.

The defense later called Doug Campbell, the lead investigator for the District Attorney's office, to the stand.

The defense called him out for a number of things, including not putting all the facts in Shelby's arrest affidavit, not having enough additional training to be a homicide investigator, and filing the arrest affidavit before the investigation was completed.

Earlier in the day, Sergeant Dave Walker (the head of the homicide division with TPD) said investigations like this one, an officer-involved shooting, typically take 30 days. The DA can take up to six months to file charges or clear someone.

The defense claimed that Campbell he didn't include any information about Terence Crutcher's PCP use in the arrest affidavit, because the toxicology report wasn't back yet.

The defense also claimed that he did not note the following facts:

-Shelby's DRE qualifications, or the fact that she thought at the time that Crutcher could have PCP in his system
-She was dealing with a non-compliant subject for almost three minutes
-She thought she was alone and did not realize she had backup there
-The fact that Officer Tyler Turnbough also felt threatened
-Three concerned citizens had called and reported Crutcher (two called 911 the night of the incident)

When the state cross-examined Campbell, he made a point to say that he had viewed the videos, photos, Shelby's statement interview, reports from the police department, and more when he filed Shelby's arrest affidavit.

The next three witnesses on the stand were the concerned citizens from that night.

The first man reported his sighting the day after the shooting. He said he and his wife drove past Crutcher, standing in the road, acting "zombie-like", with his arms outstretched, swaying back and forth.

The second woman called 911 that night after she got out of her car to try to help Crutcher. 

At first, she says Crutcher was unresponsive, ignoring her offers to help him.

After her third time asking if he needed help, he made eye contact, and then started saying, "Come here! Come here! Come look at this!" He motioned her over to the driver's side of his car.

She says she kept her distance, but when he began feeling around the dashboard, she thought he might have a gun.

She said, "This isn't a good idea, I'm out."

When she said that, he looked directly at her and then yelled, "It's gonna blow!"

She took off running to her car, and he followed her. She hopped in her car and drove away.

The witness said she drove back by about 10 minutes later, and he was standing on a nearby corner saying, "It's on fire, it's on fire."

She said he was probably talking about his car, but his car was fine.

Another witness called 911 after she said she drove by and saw him standing on the side of the road.

She said he was visibly upset, sweating heavily, saying, "It's on fire."

She said she wanted to stop and help, but it was "strange," and the whole incident "sent chills down her spine."

The trial will resume at 10 a.m. Monday morning.