“What do you think I am, a murderer?”: The Retrial of Diane Farley for the Murder of Sarah Ann Marsceill



That’s what Diane Farley said to her boyfriend, David Blatz, when he picked her up at 8 am from the house of her friend of just six weeks, Sarah Ann Marsceill, known as Sally. Diane and Sally had spent the night before drinking and doing cocaine. But David noticed what appeared to be blood stains on Diane’s clothes.

When David Stewart left his sister’s house in Dedham MA on the night of April 23, 1993, he didn’t know it would be the last time he’d ever see Sally alive. He found Sally’s body the following afternoon. She was lying face up on her bedroom floor wearing only a tee shirt. She had been stabbed eleven times and had defensive wounds on her hands and arms. The murder weapon was never found, and no motive ever established. Diane Farley was arrested and convicted of Sally’s murder.

Today’s guest is Judge Robert Cosgrove, who in 2002 was the prosecutor with the Norfolk County District Attorney’s Office in Diane Farley’s retrial. Judge Cosgrove explains how the original conviction was overturned and retrial ordered because an appellate court found the original defense attorney’s work deficient (ineffective assistance of counsel). Judge Cosgrove will also discuss the nuts and bolts of a prosecutor’s preparation for a murder trial and the inherent problems with retrying a case.