Some of the facts about Monday morning's police-involved shooting are not in question. What is in question is exactly why a Jacksonville police officer opened fire on a man who wasn't armed, at least not with a gun.

Sgt. J.T. Carey, an 18-year veteran officer, shot and killed 30-year-old Neil Southerland after a pursuit in Mandarin early Monday.

Investigators are trying to determine if deadly force was justified.

Police said Southerland intentionally rammed an officer's vehicle twice during the course of a slow-speed pursuit early Monday morning.

After the second time, officers broke out the window of the pickup truck, struggled with Southerland and tried to shut off the vehicle. Then they backed off and a police sergeant fired seven times into the pickup, killing Southerland.

"Our office is involved from the very beginning we're called out to the scene," assistant state attorney Bernie de la Rionda said.

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De la Rionda said he was the one who went out to Monday's scene. The fatal shooting happened about 3 a.m. in the 3400 block of Loretto Road, a few minutes after police said they got a 911 call about Southerland vandalizing a car in a nearby neighborhood.

"We're looking to make a determination of what the facts are, what the facts show," de la Rionda said.

Southerland's family believes those facts will show he was shot and killed without justification.

Police said they saw Southerland's truck leaving the neighborhood and tried to pull him over. Officers said Southerland twice stopped his pickup truck with a trailer attached, and both times he backed up into a police cruiser. The second time, the trailer rode up onto the hood of the patrol car, almost to the windshield.

One of Southerland's family members said Wednesday Southerland was not a bad guy and was simply trying to get to his father's home, just a few blocks away from where the shooting happened.

The Jacksonville Sheriff's Office is also investigating Carey for the second time.

Carey was in a similar situation in 1999 when he shot and killed an 18-year-old he believed had stolen a pack of cigarettes. Police said James Jackson was shot after struggling with the officer for his gun.

"The last thing we want to do is use deadly force if we don't have to," said Nelson Cuba, the president of the Fraternal Order of Police, who said he's a friend of Carey's.

Cuba said until the facts of the case come out, it's hard to judge, but added he believes deadly force would not have been used unless Carey feared for his life.

"To have to take someone's life is not something that we take lightly or go out at the beginning of our shift and say, 'Oh, this is what we want to do today,'" Cuba said.