Martens, a 31-year veteran of the FBI who had high-level security clearance, claimed he hit Jason Corbett on the head with a baseball bat in self defence.
“I hit him until he goes down and then I step away,” Martens testified on direct examination.
“I don’t know how many times I hit him. I hit him until I thought he could not kill me. I felt both of our lives were in danger. I did the best I could.”
Assistant District Attorney Greg Brown asked Martens in cross-examination a number of questions about his FBI training, particularly in the area of self-defence.
Martens said he was taught how to shoot and how to defend himself against a knife attack, among other things. He also was taught to use judgement when using force and that law enforcement officers are allowed to use deadly force if their lives are threatened.
Brown also suggested out of the presence of the jury that Mr Martens and Ms Martens may have killed Jason Corbett because he had a $600,000 life insurance policy through his company.
On the night of the alleged murder, Martens and his wife, Sharon, had plans to have dinner with a few friends. Those plans were later cancelled, and Martens said he and his wife decided to drive to visit Molly.
The Martens got to Davidson County about 8.30pm on August 1, 2015, and had pizza with Molly, Jason and Sarah. Jack had gone to a friend’s party nearby and came home about 11.
Martens testified he had gone to bed with plans to play golf with Jason the next day. Then the unthinkable happened.
“I heard thumping, loud thumping, loud footfalls,” he said. “I heard a scream and loud voices. There was an obvious disturbance going on above me.”
Martens said he got out of bed and grabbed the baseball bat he had planned to give to Jack the next day and went upstairs. By the time he got upstairs, he said the sounds were coming from the master bedroom where Jason and Molly were. He opened the door.
“In front of me, I would say seven or eight feet...in front of me, Jason had his hands around Molly’s neck facing each other. She was a little to the right. He was a little to the left,” he said.
At some point, Martens said, Jason turned Molly around and placed her into the crook of his right arm.
“I said, ‘Let her go.’ He said, ‘I’m going to kill her.’ I said, ‘Let her go.’ He said, ‘I’m going to kill her,’” Martens said, starting to choke up. “He was really angry. I was really scared.”
Jason Corbett takes a step toward the hallway that goes to the bathroom. “I was afraid he was going to get to the bathroom and that would be the end of that,” he said, again choking up.
Martens said he took a step to the right and hit him in the back of the head with the baseball bat. “It seemed like the most effective place to hit him,” he said. “I didn’t want to hit Molly.”
Jason started to move toward the bathroom and Martens said he followed. He said he had little room to manoeuvre. Then they move back toward the bedroom.
“I get what I think is a chance to hit him,” Martens said. “Only this time, he puts up his left hand and catches the bat, perfectly right in his palm.”
Molly escapes at that moment, Martens said. Jason then pushes Martens with his left hand across the bedroom, he said.
Martens said he thinks his glasses have fallen off and looks for them and then realises he has to do something. Molly is by the nightstand. Jason is looking at Martens and Molly, Martens said.
“I decide to rush him and try to get hold of the bat,” he said. The two men struggle over the bat, and then Martens gets control. Then Martens said he hits Jason with the bat, again and again until Jason is down.
Martens was asked whether he intentionally killed Jason Corbett.
“No, sir,” he said. “I made the decision to hit (Jason) in the back of the head in an effort to end the threat to my daughter.”