Then, Gerry's Italian Kitchen became a focal point again on April 24, nine days after the Marathon bombing, after investigators removed two Planet Aid charity donation bins from a parking lot it shares with a neighboring grocer. A driver had discovered discarded fireworks inside and law enforcement sources told ABC News the gunpowder had been removed from the cartridges.
It is unclear how the Tsarnaev brothers were associated with Gerry's Italian Kitchen, if at all, but looking back, multiple residents of Waltham and Watertown remember Tamerlan Tsarnaev delivering food to their homes and Tsarnaev family members have told reporters the brothers worked as pizza deliverymen. The eatery's management, however, steadfastly denied that either Tsarnaev brother worked there.
Scott Wood, a jiu jitsui trainer who befriended and trained Mess at a martial arts studio in Vermont, said he always believed whoever the killer or killers were, they got in Mess' home "under the guise of being a friend."
"Brendan was a tough, tough kid, a strong kid. It wouldn't have been easy to take him out like that," Wood told ABC News.
Wood and other friends met Tamerlan with Mess at a June 2011 fight event. Mess introduced Tamerlan as "Tam" but fighters also recognized him from his Golden Glove victories and called him "Champ." Tamerlan did not drink and was very quiet that night.
That was the last time Wood saw his friend alive.
As detectives probe the Waltham connections, Middlesex County prosecutors are also busy building a case against Dzhokhar Tsarnaev in connection with the cold-blooded killing of MIT Police Officer Sean Collier after the Marathon bombings.
Collier was shot five times, allegedly by the Tsarnaev brothers, as he sat in his cruiser, just days before he would have become a Somerville Police Officer. Collier's murder will be prosecuted by state prosecutors while the Marathon bombing will be tried in federal court.
Collier's murder was followed by a carjacking that spawned a wild, high-speed chase that ended with bombs exploding and bullets flying on a street corner in Watertown. Tamerlan Tsarnaev was pronounced dead at Beth Israel Hospital later that night. His brother escaped but was found badly wounded in a Watertown man's boat blocks from the gun battle the following evening.
Dzhokhar Tsarnaev is being held in the infirmary at Fort Devens federal prison.
Freelance writer Michele McPhee is a Boston-based reporter and frequent contributor to ABC News. ABC News' Aaron Katerksy contributed to this report.