A 53-year-old Seattle man died last week, six days after he was struck in the head with a hammer in what King County prosecutors say was an unprovoked attack.

Shawn Grenzebach never regained consciousness after the Jan. 13 attack near Pike Street and Third Avenue, dying late Thursday at Harborview Medical Center, according to prosecutors and Seattle police. His death marks Seattle’s fifth homicide so far this year.

Prosecutors expect to file amended charges next week against Christopher Eugene Martin, 34, who was charged before Grenzebach’s death with first-degree assault and robbery and remains jailed in lieu of $250,000 bail. Martin is scheduled to be arraigned Feb. 2.

The deadly bludgeoning occurred after Seattle police saw Martin waving a hammer and yelling at people on the street and Grenzebach using an orbital grinder to cut the lock off a bicycle, according to the charges against Martin.

A Metro bus pulled up, blocking officers’ view, but by the time one of the officers walked across the street, Grenzebach was unconscious on the sidewalk, the charges say. A woman yelled at the man’s assailant, asking why he had struck the victim, and the officer saw him step over Grenzebach’s body, scoop up Grenzebach’s backpack and walk away, according to the charges.

Another witness told police that after Grenzebach fell to the ground, the attacker stood over his body and said, “I told you not to do that” — an apparent reference to Grenzebach’s efforts to cut the lock from the bicycle.


That witness photographed the attacker and later gave his photos to police, the charges say. He told police Grenzebach was struck from behind — a statement corroborated by footage captured by video cameras on the bus, according to the charges.

Martin had Grenzebach’s backpack, as well as a hammer, when he was arrested nearby moments later, the charges say.

Other Seattle police officers performed CPR on Grenzebach until medics arrived and took him to Harborview, where he underwent surgery for a skull fracture and later died, charging papers say.

Martin, who has a lengthy criminal history, was charged in February 2022 with second-degree robbery but was released from jail in May so he could get treatment at a Port Angeles behavioral-health facility, according to Casey McNerthney, a prosecutor’s spokesperson. The robbery case remains pending.

The Jan. 13 hammer attack was strikingly similar to an August bludgeoning at Third Avenue and Pike Street, when 66-year-old Rodney Peterman was struck in the head from behind with a metal pullup bar. His attack was also witnessed by a Seattle police officer, and his alleged assailant, Aaron Fulk, 48, was quickly arrested.

Peterman died a few days later at Harborview. Fulk was charged with first-degree murder and remains jailed in lieu of $2.5 million bail.