The murder trial of Zachary Carr continues.Carr is on trial for allegedly shooting and killing 19-year old John Bobby Surles in January of last year.On Monday, jurors heard opening statements from the prosecutor and defense.Tuesday’s proceedings put Zachary Carr’s father, Richard Carr, on the stand. Carr testified that about three weeks before the shooting, he bought his son a hand gun. He says Zachary Carr had been complaining that someone was threatening his girlfriend. Carr told the jury he didn’t give his son the gun right away, but on January 27th, the day Surles was shot, he met up with him in Bangor to give him the gun. Carr says that gun had live ammunition in it when he dropped it off.That night, Surles was shot on Cumberland street and died two days later.Tuesday morning, jurors visited that street and a nearby apartment.Carr’s defense attorney says going to the scene will play a critical part in his case. “It gave them the opportunity to really see the lay of the land here. There’s a lot of information that you can learn from actually visiting the scene where the event occurred. I think that the more information the jury has about this event the more likely it will be that Zach is acquitted of all counts.”The prosecution claims Surles was unarmed and on the ground when he was shot by Carr.But the medical examiner who conducted the autopsy on Surles testified today that she believes the shooter and Surles were both standing when he was shot.The state is expected to call one more witness to the stand on Wednesday.