A 42-year-old man was fatally stabbed Sunday night on a gritty block in the Polk Gulch neighborhood of San Francisco, officials said.

The victim, who was not identified, was stabbed with an “edged weapon” sometime around 10:25 p.m. on the 900 block of Geary Street, police said.

Paramedics took the man to San Francisco General Hospital, where he succumbed to his injuries.

On Monday morning, several workers on the block of Geary between Larkin and Polk streets identified the sidewalk where the victim was found by a small trail of blood next to a piece of police tape near a flower shop.

Police haven’t “determined the exact location where the stabbing occurred, whether it was on the sidewalk or in a building. It’s still all under investigation,” said Officer Robert Rueca, a spokesman for the San Francisco Police Department.

No one would give their names on the record, but people in the neighborhood said the victim was a resident of the nearby Hotel Heartland, a single-room-occupancy hotel two doors from where the killing happened.

Workers at Hotel Heartland said they were told not to say anything about the incident.

The owner of Ann’s Flowers and Balloons, not far from the bloody trail, said police came by her business Monday morning to collect security video from cameras outside of her business.

Investigators were working to piece together a motive and the circumstances of the killing as they hunt for a suspect.

The killing is the 30th so far this year in San Francisco. At this same time last year there were 44 killings in the city, police said.

San Francisco had gone more than a week without a homicide before Sunday’s killing during one of the most violent months of the year, statistically.

The last person killed in the city was 19-year-old Gerson Romero, who was shot Aug. 11 in a hail of gunfire that wounded four others in the city’s Crocker-Amazon neighborhood.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky