As a female waited at an Anacostia bus stop on Sunday afternoon, trouble arrived before her transportation did.

Four young men surrounded her, and two of them tried to sexually assault her. Only a passerby who came to her aid saved her from further harm, D.C. police said.

Detectives are searching for the suspects in the 5 p.m. attack in the 1800 block of 13th Street SE, officials said. When the passerby, who was not identified, intervened, the assailants stopped their assault, grabbed property from the victim and fled, police said.

It was not clear how old the female was.

Authorities were given detailed descriptions for two of the attackers. Police described the first as a dark complexioned black man, between 18 and 20 years of age, who is 6 feet tall. He was described as having dreadlocks and crooked teeth. He wore a red T-shirt and blue sweat pants.

The second suspect was described as a five-foot-eight, light-skinned black man, who is between 18 and 20 years old. His hair was short, and he wore white and yellow Michael Jordan sneakers.