Tyler Sumner, of North Adams, was found guilty on May 31 of first-degree murder and possession of ammunition without FID card, the Berkshire County District Attorney's Office said.
Pittsfield police responded to 66 South John Street, where 911 callers said they saw two masked men prowling the area. While they were still enroute, they heard two gunshots.
Officers found Olivieri desperately gasping for breath in the driver's seat of her car as blood trickled from a bullet wound to the side of her head, the prosecutor said. Police attempted life-saving measures, and paramedics rushed her to Berkshire Medical Center, where doctors pronounced her dead.
Multiple people told investigators that Sumner had plans to kill someone living in that area, but they didn't believe Stephanie Olivieri was the intended target, the prosecutor said.
Police found eight bullet cases around her car and several holes in the vehicle. There was no return fire, investigators testified.
Berkshire County District Attorney Timothy J. Shugrue said Oliveri was an innocent bystander who was trapped in the middle of a fight she had no part in.
Today justice was served in the tragic death of an innocent bystander, Stephanie Olivieri; however, this guilty verdict will do nothing to bring her back. Tyler Sumner murdered Ms. Olivieri while she sat in a car filled with gifts and decorations for her child’s birthday. She was preparing to celebrate a wonderful event when her life was ruthlessly cut short.
Click here to follow Daily Voice Deerfield-Sunderland and receive free news updates.