The trial of a man accused of killing his co worker in Kingston begins in Ulster County. Prosecutors say David Reese shot Aron Thomas at the Department of Environmental Protection building in Kingston last year. Candace Dunkley has more.

KINGSTON, N.Y -- On Wednesday the trial began for David Reese of Gilboa, who is charged with murder in the second-degree.

The prosecution said that in February of last year Reese killed his co-worker 33-year-old Aron Thomas, of Olivebridge, after shooting him in the neck at the Department of Environmental Protection building in Kingston, where both men worked. 

“Aron Thomas went to work like many of us did that day. Within one hour he was dead,” said Ulster County Assistant District Attorney Katherine VanLoan.

The prosecution said that Reese said that Thomas was stalking him and had broken into his home. But the prosecution said that doesn’t quite add up.

“But you will hear the defense also told 911 that he lives in Gilboa NY. And that this burglary already had been reported to the sheriff’s office,” said VanLoan.

But the defense said that Reese did believe that he was being stalked which contributed to his mental state.

“Listen carefully to the evidence as it develops and you will hear, to put it mildly, there was a strained relationship between those two men," said Dutchess County Assistant Public Defender Jeff Hoerter. Hoerter is representing Reese because of a conflict in the Ulster County public defender's office. 

The defense says that Reese is not guilty and that while Reese caused Thomas' death but he didn’t intend to kill him. 

“Those are the kind of things that makes Mr Reese’s mental state was he acting with emotion was he acting with an extreme amount of emotion. In essence it comes down to was he acting with an intent to kill,” said Hoerter. 

If convicted Reese could spend up to 25 years in prison.