Holmes was taken to a local hospital, where he was pronounced dead. A preliminary investigation revealed suspects had approached the vehicle and opened fire before fleeing, Silbert said.
He said he did not know for whom the procession was being held.
Another shooting, in which a 30-year-old man was wounded, occurred in Penrose on Wednesday.
Baltimore police also identified on Monday two other men killed a day apart in the same neighborhood late last week.
Montrel Rivers, 20, of the 4000 block of Eierman Ave., was fatally shot in the upper body in a double shooting outside of a convenience store in the 1100 block of East North Ave. in East Baltimore Midway at about 2:30 p.m. Thursday, police said.
Rivers was pronounced dead at a local hospital. The other victim in the shooting, an unidentified 22-year-old man, was shot in the leg and taken to a local hospital for treatment, police said.
At about 8:50 p.m. Friday, Ronald Preston, 30, of the 800 block of Montpelier St., was found suffering from gunshot wounds in the 600 block of Gutman Ave., also in East Baltimore Midway, police said.
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Preston was taken to a local hospital, where he was pronounced dead.
As of Monday, there had been 47 homicides in Baltimore in 2018. That is fewer than during the same period last year, but more than during the same period in each of the previous five years.
The 342 homicides in 2017 marked a per-capita record in Baltimore. It was the third year in a row the city had surpassed 300 killings — a mark not previously reached in the city since 1999.
Mayor Catherine E. Pugh — who fired former Police Commissioner Kevin Davis in January and appointed Darryl De Sousa in his place — said Monday in a State of the City address that the city is moving in the right direction, but still has more work to do to halt the violence.
She said the “collateral damage” from homicides is generational and leaves long-term wounds.