SKOWHEGAN — The prosecution called its last witness this morning in the murder trial of Jay Mercier of Industry.

State police Detective Adam Kelley testified that he and Detective Bryant Jacques told Mercier in April 2011 that police had DNA and other evidence that linked him to the killing of 20-year-old Rita St. Peter in Anson in 1980.

Mercier said that the accusation was impossible and he didn’t believe it, according to Kelley.

Attorneys defending Mercier, 57, will present their case in Somerset County Superior Court after prosecutors finish with theirs.

In recorded interviews with Jacques in 2010 played in court on Tuesday, Mercier stuck to the story he has told ever since he became a suspect in the murder 32 years ago: He did not know St. Peter, had never met her, had never picked her up in his truck and never had sex with her.

He kept to the story, even when confronted with DNA evidence pointed to his having had sexual contact with St. Peter.