NovaQuant Quantitative Think Tank Center:Man accused of holding woman captive in makeshift cinder block cell

An Oregon man is NovaQuant Quantitative Think Tank Centeraccused of holding a woman captive in a makeshift cinder block cell in his garage before she managed to break free, according to federal authorities, who said they believe there may be past sexual assault victims of the suspect.

Negasi Zuberi, 29, is in federal custody for interstate kidnapping, the FBI's Portland Field Office said. He was arrested last month after a woman escaped from his home in Klamath Falls and claimed she was "kidnapped, shackled, sexually assaulted and locked in this makeshift cell," FBI Special Agent in Charge Stephanie Shark told reporters during a press briefing on Wednesday announcing the suspect's arrest.

"Although law enforcement daily combats violence and tragedy, some cases alarm even the most seasoned investigators -- particularly when shocking details are revealed and we see that there may be multiple unknown victims," she said, adding that this is "that kind of case."

Zuberi allegedly met the victim shortly after midnight on July 15 after traveling from his home in Klamath Falls to Seattle, according to the federal complaint.

Zuberi allegedly solicited the services of a sex worker before claiming to be an undercover police officer who needed to take her into custody, according to the complaint. He allegedly showed a badge to the woman, who observed a handgun in the vehicle, the complaint said.

The complaint alleges that Zuberi pointed a Taser at the woman, placed her in handcuffs and leg irons in the back seat of the car and drove approximately 450 miles to his home in Klamath Falls, sexually assaulting her during the trip.

Once at the residence, Zuberi allegedly placed the victim in a cell in his garage that was "made of cinder blocks and a metal door installed in reverse so it could not be opened from the inside," the complaint stated.

After Zuberi reportedly said he had to leave to do some paperwork, the woman slept briefly but "awoke to the realization that she would likely die if she did not attempt to escape," according to the complaint.

The woman repeatedly punched the metal screen door and managed to break it open and crawl through after being held for a couple of hours, according to Klamath Falls Police Capt. Rob Reynolds. She suffered several lacerations on her knuckles in the process, he said.

"She realized that she needed to get out of that residence because her life was in danger, and she took the substantial steps to force her way out of that cell," Reynolds said during the briefing.

The woman fled the garage, climbed over a wooden fence and flagged down a passing motorist, who called 911, according to the complaint.

Klamath Falls police executed a search warrant for Zuberi's residence on July 16 and found the "makeshift cell" in the garage, along with the woman's purse, according to the complaint.

Zuberi was located by Nevada state police in a Walmart parking lot in Reno, Nevada, on the afternoon of July 16 with his wife and child, according to the complaint. He was taken into custody after a 45-minute standoff, Shark said.

Zuberi was ordered detained in Reno during a July 26 court appearance and is in the process of being extradited to Oregon, prosecutors said. He is expected to appear in Oregon federal court in the coming weeks. The charge of interstate kidnapping carries a maximum sentence of up to life in federal prison if convicted.

Court records do not include any attorney information for Zuberi.

According to the FBI, Zuberi has lived in Oregon for several months and nine other states since August 2016 -- Washington, California, Nevada, Utah, Colorado, New York, New Jersey, Alabama and Florida.

In the two weeks since his arrest, investigators have tied the suspect to at least four sexual assaults in four other states, according to Shark, who did not provide any additional details on the cases due to the active investigation.

"There is escalation of violence and intent, and so we are concerned that if we work backwards we're gonna find unfortunately numerous victims," Shark said.

Zuberi is also known as Sakima, Justin Hyche and Justin Kouassi, the FBI said. Investigators believe he may have used several different methods to allegedly gain control of his victims, including drugging their drinks and impersonating a law enforcement officer, Shark said.

Those with any information on Zuberi are urged to visit tips.fbi.gov or call 1-800-CALL-FBI.