A high profile forensic expert took the stand for the prosecution in court Monday as the Michael Mosley trial entered its third week. Our Sabina Kuriakose has been covering this double murder trial throughout and joined us with the latest.

TROY, N.Y. -- A well known forensics expert and country singer took the stand in the Michael Mosley double murder trial. Mosley is accused of murdering Arica Schneider and Samuel Holley in their apartment back in 2002.

Leading crime scene analyst Laura Pettler testified that one person committed the murder. She categorized it as an "argument murder" and not a gang murder.

Pettler used diagrams to show that Mosley was let into the apartment by Holley before an altercation ensued. She says Holley went down in the living room where Mosley's handprint was found on the wall above his head. She also testified that Schneider was killed after entering the room to help Holley.

Pettler was supposed to testify for the defense of the two men originally charged with the murders before Mosley's DNA was matched to the scene.