By Maria Cramer Globe Staff

The city of Boston unveiled a sign Friday honoring Officer John Gallagher, who was killed in a 1962 bank robbery.

Boston Police Officer John J. Gallagher wasn’t supposed to be working that early morning shift in Kenmore Square. But the father of three small children had switched nights off with another officer, so when a burglar alarm at the Shawmut National Bank branch went off, Gallagher and his partner were among the first to respond.

In the shadowy basement of the bank, Gallagher found Charles E. Tracey, a 37-year-old cook with a minor record. He had broken into the bank and was holding a long-barrelled .38-caliber firearm he had found inside a closet, according to news accounts of that confrontation on May 25, 1962.

Tracey fired first, striking Gallagher in the abdomen and right leg at point-blank range. The officer managed to fire back, hitting Tracey three times. Tracey was struck twice more by other officers, but survived. Gallagher, however, died at 6 a.m. at Beth Israel Hospital, three hours later.

He was 33 years old and the 50th Boston police officer at the time to die in the line of duty.