The Springfield Republican reports court documents show DNA evidence from the victim's fingernails was a key to an arrest in the fatal stabbing of a Chicopee woman two years earlier.
The state police investigator's report was released Tuesday in district court after the newspaper challenged prosecutors' efforts to impound it.
Twenty-three-year-old Dennis Rosa-Roman was charged in November with the first-degree murder of 20-year-old Amanda Plasse in 2011. He has pleaded not guilty.
The documents say someone broke into Plasse's apartment not long before her death, and she believed the burglar was a neighbor she planned to confront. They don't indicate why it took two years to make an arrest.
Police handling of the case drew controversy after a patrolman and a sergeant took cellphone photos at the crime scene and shared them with other officers.