LOS ANGELES (AP) – Investigators are searching for a man they believe has sexually assaulted at least a dozen female sex workers at gunpoint in the Los Angeles area since 2014, police said Friday.

The most recent attack occurred Friday morning in the Compton neighborhood and detectives have linked that to 11 other cases being investigated by both Los Angeles police and the Los Angeles County sheriff’s department, police Capt. William Hayes said.

The man has approached each of the women while they are working as prostitutes in south Los Angeles and solicited them for sex. Once they get into his car, he pulls out a gun, drives them to a remote area and sexually assaults them, Hayes said.

The suspect threatened to hurt the women and in at least one case beat a victim who fought back, he said. The victims have ranged in age from 15 to 46 years old.

Detectives linked the cases in May after DNA from a sexual assault investigation matched a DNA that was on file from a sheriff’s department case in December 2014. As they began investigating, they soon found a unique pattern and began linking other cases, Hayes said.

“We are concerned about the safety of the young ladies involved in these crimes,” Hayes told reporters. He said detectives are reaching out to commercial sex workers and outreach organizations to warn them.

Investigators have only a vague description of the suspect, who they believe is a black man, who is between 5-feet-8 and 6-feet tall and weighs between 180 and 220 pounds, Hayes said. The victims have said the suspect is bald and has a salt-and-pepper goatee and is believed to be between 30 and 50 years old.

Copyright 2017 The Associated Press.