Colleen M. Tanguay

Colleen M. Tanguay testified for the prosecution on Day 38 about processing the Laurel Street crime scene in Watertown after the April 19, 2013 confrontation. The Massachusetts State Police trooper said she arrived around 2:15 a.m., but processing began around 6:15 a.m. while officers searched for a suspect and cleared bomb parts and devices. As case officer, she oversaw documentation across four areas, each staffed with a photographer, videographer and scribe.

Fourteen photographs were admitted without objection. Tanguay used them to identify the Ruger at 55 Laurel Street, backpacks, ammunition, shell casings, bomb pieces and a pressure cooker embedded in a vehicle. She described individual packaging and glove use to preserve fingerprint evidence, confirmed bullets in houses and cars, and estimated more than 250 ballistics items within approximately 450 or more total evidence items in her logs. She qualified some photographic identifications as apparent or possible shell casings and was unsure whether the Ruger was semiautomatic.

On cross-examination, Tanguay distinguished a pellet gun found behind the Honda from the Ruger found in the driveway. When questioned about pellet-gun operation, she acknowledged that she had never fired one. That qualification concerned her familiarity with the separate item, rather than retracting her account of the scene's firearm and explosive-device evidence.