MIAMI BEACH, Fla. -

The trial continues Wednesday for the man accused of shooting and killing a Miami police detective in January 2008.

Opening statements began Tuesday in the first-degree murder trial of Andrew Rolle, 26, who claims he was acting in self-defense when he killed James Walker.

On Wednesday prosecutors showed the jury an AK-47 found at the crime scene, and which they believe is tied to Rolle. The claim Rolle used the assault rifle to shoot at rival gang members in North Miami Beach, and then tried to run away.

Walker was off-duty and sitting in his unmarked Ford Taurus while visiting his ex-wife. Investigators believe Rolle mistook Walker’s car for his getaway car. When Rolle was unable to open the car door, he shot the officer.

But the defense says it was an act of self-defense, because Walker pulled out his gun first, and Rolle didn’t know that Walker was a cop.

On Wednesday a North Miami Beach police captain took the stand.

"Every family deserves the right to know what happened," said Capt. Richard Rand. "Because it was an officer, we did come together in an attempt to find out what happened to make sure we got answers. It was a big case for us."

The trial is expected to wrap up next week.