Negasi Zuberi, 29, allegedly snatched the unnamed victim off a street in Seattle on 15 July before driving her around 450 miles to his rented home in Klamath Falls, Oregon - a seven-hour journey - and locking her in the garage.

"This woman was kidnapped, chained, sexually assaulted and locked in a... cell," Stephanie Shark, assistant special agent in charge of the FBI's field office in Portland, Oregon, said in a statement.

"Police say she beat the door with her hands until they were bloody in order to break free."

Now officers are looking for other possible victims after linking Zuberi to sexual assaults in at least four other states.

The woman's "quick thinking and will to survive may have saved other women from a similar nightmare," Ms Shark added.

Investigators say Zuberi - who also used the names Sakima, Justin Hyche and Justin Kouassi - solicited the woman, identified only as Adult Victim 1, to engage in prostitution along Aurora Avenue in Seattle, an area known for sex work.

He allegedly claimed to be an undercover police officer, showing a badge before pointing a stun gun at her and placing her in handcuffs and leg irons.

He then put her into the back of his vehicle before driving home - stopping to sexually assault her on the way, the victim said.

Victim realised 'she would likely die' if she didn't try to break free

Adult Victim 1 was put in the cell built from cinder blocks (concrete breeze blocks) - with metal bars on the door.

She said she "briefly slept and awoke to the realisation she would likely die if she did not attempt to escape".

"She repeatedly punched the door with her own hands," said Klamath Falls Police Captain, Rob Reynolds.

"She had several lacerations on her knuckles."

The woman broke some of the door's welded joints to create a small opening which she climbed out of, Capt Reynolds added.

She flagged down a passing driver who alerted police.

Zuberi allegedly fled after the woman escaped but was arrested by state police in a car park in Reno, Nevada, several hours later on 16 July.

He was in his car holding one of his children and talking to his wife, who was standing outside, when officers arrived.

He initially refused to get out of the vehicle but eventually surrendered.

Zuberi has been charged with interstate kidnapping and transporting an individual across state lines with intent to engage in criminal sexual activity.

If convicted, he could face life behind bars.

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Investigators say a purse belonging to Adult Victim 1 was found during a search of Zuberi's home, together with handwritten notes, one labelled "Operation Take Over".

The notes included a list saying "Leave phone at home" and "Make sure they don't have a bunch of ppl (sic) in their life. You don't want any type of investigation".

Another document showed a sketch of an underground structure using concrete blocks, foam insulation and waterproof concrete.

Defendant rented home from city's mayor

The house, on a residential street, is thought to be owned by Portland Mayor, Carol Westfall and her husband, Kevin, according to property records.

They evicted Zuberi following his arrest.

The Westfalls said: "We are shocked and dismayed by what has occurred.

"We applaud the actions of the woman who helped capture this person and prevent him from committing further atrocities."

Zuberi is feared to have drugged women's drinks in an attempt to gain control of them, the FBI said.

The bureau is setting up a website asking anyone who believes they could be a victim of Zuberi to come forward.

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