SAN FRANCISCO — Police on Saturday were investigating the killings of four men shot to death in a car in a trendy San Francisco neighborhood.

The four were attacked around 10 p.m. Friday in the Hayes Valley district, and they died at the scene, police spokesman Albie Esparza said. Police on Saturday were trying to determine the make and model of a car that witnesses saw speeding from the scene, and to determine if it was linked to the killings, Esparza said in a statement.

Residents of Hayes Valley, an area that includes popular restaurants, shops and art galleries, called police emergency lines Friday night to report hearing at least 15 shots, the San Francisco Chronicle reported. San Francisco broadcaster KGO reported some bullets struck inside surrounding homes, including one that lodged in a refrigerator.

The car in which the men were found had been reported stolen, police said.

By early Saturday, police had covered parts of the shooting scene with yellow tarps. Police cordoned off several blocks, and they canvassed the area for witnesses.

Police alerted the California Highway Patrol that a vehicle possibly linked to the violence could be headed toward the Pacific Coast Highway, the newspaper said.