Aaron Powell, 40, is accused of killing his estranged wife Christina, 35, and her friend, Mario Masciarelli, 24, at the Powell's home in March of last year.
One of the people who took the stand today was a DNA analyst with the New York State Police.
The analyst, Brian Murphy, tested about 35 items that were collected as evidence, including a baseball bat with blood on it, cigarette butts, and clothing.
The prosecution says that Powell killed Masciarelli with a baseball bat by hitting him over the head with it numerous times and then strangled Christina in the basement.
Murphy also explained how DNA evaluation works and his process in working the case.
Powell's trial, which he is not present for, continues Wednesday morning.
The prosecution may rest its case on Wednesday.
Copyright 2016 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.