Officer on the stand describes shooting of unarmed black man

CHARLOTTE, N.C. -- A North Carolina police officer was back on the witness stand in Charlotte today. The officer, who is white, is charged with voluntary manslaughter in the shooting death of an unarmed black man.

Officer Randall Kerrick said it was kill or be killed in September of 2013.

"He was going to assault me," he said. "He was going to take my gun from me."

A woman had called 911 to report a home invader banging on her front door. But 24-year-old Jonathan Ferrell may have just been looking for help after a single-car accident.

Kerrick and other officers responded. They said Ferrell was acting erratically. One fired his Taser at him. In this dashboard camera video, you can see the Taser's dot and Ferrell run past.

"The suspect began aggressively coming towards me," Kerrick testified.

"How loud were your commands?" his lawyer asked.

"Get on ground, get on ground, get on ground," Kerrick yelled on the stand.

Kerrick shot Ferrell 10 times during their struggle.

"No matter what I did, he wouldn't stop," he said on the stand.

"What did you believe at that time?" his lawyer asked.

"I thought I was gonna die," Kerrick said.

Farrell was unarmed and had no criminal record. Charlotte-Mecklenburg police fired Kerrick for excessive force.

Prosecutor Therea Postell grilled him on the stand. And pointed out the officer's inconsistencies.

Georgia Farrell is the dead man's mother. Three days after his death, she talked to CBS News about Officer Kerrick.

"But I forgive him," she said. "I so forgive him, but I do want justice."

Georgia Farrell told CBS News her son always respected police, because his sister is a police officer.

If convicted, Kerrick could face up to 11 years in prison.