PORTLAND, Ore. (NewsNation) — A man who allegedly held a Seattle woman captive inside a homemade cinder block dungeon in Oregon was well known to sex workers in the Portland area, many of them told NewsNation.

Several of the women said they recognized the suspect, 29-year-old Negasi Zuberi, immediately. They described him as an aggressive harasser and many knew to avoid him.

According to one local veteran in the industry, girls on the streets are especially vulnerable and criminals often exploit that.

Elle Stanger is a certified sex educator and sex worker who told NewsNation that she’s glad the victim in Klamath Falls was able to escape the makeshift dungeon.

“These people can fly under the radar when they target people who don’t have a lot of rights,” Stanger said. “I wonder what she’s (the victim) been through before. “I’m so happy for her that she could fight back and not let this guy win, because it sucks when the bad guys get away with stuff.”

In northeast Portland, a two-mile stretch of 82nd Avenue is known for prostitution, and it was also known to Zuberi. Sex workers say many in the area are often afraid of going to law enforcement.

“If they have any vulnerabilities … there’s a huge power dynamic disparity,” said Stanger. “Like someone who doesn’t have a lot of rights isn’t going to be able to say ‘No.’”

Some women told NewsNation they were afraid to speak up because Zuberi allegedly posed as an undercover cop.

FBI Special Agent in Charge Stephanie Shark told NewsNation’s “Banfield” she’s worried sex workers are generally afraid to come forward.

“His (Zuberi’s) behaviors have indeed been escalating based off of the information that we’ve identified … This was definitely not the end,” Shark said. “The fact that we saw a makeshift cell in a garage that we knew several months prior was not there? … To see plans for something that he would build underground to house prisoners? It speaks for itself.”

Since FBI agents in Oregon announced details of the case last week, including Zuberi’s ties to 10 states using various aliases, the FBI has been able to determine that healso spent time in Chicago in January of 2019 and in Ecorse, Michigan, a Detroit suburb, in April of 2017.

That brings the total to a dozen states where there may be potential victims.

The FBI has not said how many tips about potential victims have come in, but sources told NewsNation that information is matching up to the multiple states where he has spent time, along with the rough timeline, which appears to overlap, since he was often on the move.