SAN FRANCISCO (AP) – A California woman and her boyfriend say kidnappers entered their house in the middle of the night last week, abducted the woman and held her for ransom before releasing her two days later. Police have expressed skepticism about their claim. Here are some things to know:

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WHAT HAPPENED?

At about 2 p.m. on March 23, 30-year-old physical therapist Aaron Quinn called police to report that his girlfriend was abducted from their San Francisco Bay Area home in the pre-dawn hours.

Quinn’s lawyers say he awoke to a bright light in his face, and two kidnappers bound and drugged him.

The strangers then took 29-year-old Denise Huskins, also a physical therapist, from the couple’s Vallejo house, and demanded an $8,500 ransom, Quinn told police.

Quinn was prepared to pay the amount, according to his attorney Dan Russo. However, Huskins turned up the morning of March 25 in her hometown of Huntington Beach before it was due.

She called her father and said she was dropped off at her mother’s home, found no one there, and walked 12 blocks to her dad’s apartment.

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HOAX OR KIDNAPPING?

Hours after Huskins called her father, Vallejo police revealed they found no proof of a kidnapping and believed it was a hoax.

“It was such an incredible story, we initially had a hard time believing it, and upon further investigation, we couldn’t substantiate any of the things he was saying,” Vallejo police spokesman Kenny Park said at a March 25 news conference.

However, Quinn and Huskins have maintained through their attorneys that it wasn’t a hoax.

Huskins’ lawyer Doug Rappaport said his client talked at length with detectives “with the hope of clearing her name because she is absolutely, unequivocally, 100 percent, positively a victim.”

Police have since declined to comment other than to say they continue to investigate.

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ANONYMOUS EMAIL

On March 24, while Huskins was still missing, the San Francisco Chronicle received an email from an anonymous person claiming to be holding her.

According to the newspaper, the person wrote that Huskins was in good health and would be returned safely the next day.

“Any advance on us or our associates will create a dangerous situation for Denise,” the sender wrote. “Wait until she is recovered and then proceed how you will. We will be ready.”

The email included an audio file of a woman identifying herself as Huskins. Her father, Mike Huskins, confirmed it was her voice, the newspaper reported.

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MORE MESSAGES

On Tuesday, the Chronicle reported it has received additional emails from a person claiming to be one of Huskins’ kidnappers, including one demanding that police apologize to Huskins for calling it a hoax.

The emails contained a threat to Vallejo police and specifically Park. The anonymous person called for an apology by noon Tuesday.

“I/we may be the direct agent of harm. But it will be made crystal clear that the Vallejo Police Department, and you, Mr. Park, had every opportunity to stop it,” the sender wrote.

The Los Angeles Times also reported that it received an anonymous email about the case. That email said: The Mare Island kidnapping was a training mission to test means and methods that would be used on higher net worth targets.”

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MYSTERY SENDER

The origin of the emails remains a mystery.

None of them are signed, and they appear to come from dummy accounts with names like huskinskidnapping@hotmail.com. An email message sent to that address by The Associated Press was not returned.

The FBI has declined to comment on the emails, but a spokeswoman said the agency is aware of them.

Meanwhile, an official from the Solano County District Attorney’s Office has said prosecutors are consulting with police on the case.

Quinn and Huskins remain free, neither charged with any crimes. The two are physical therapists who met on the job and began dating last year.

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NEW DEVELOPMENTS

In an unusual development, an East Bay man has been arrested in connection to the kidnapping of the Vallejo woman whose case was believed to be a hoax.

Mattew Muller, 38, of Orangevale, Calif., who has been in custody for a home invasion robbery in Dublin, is now being accused of snatching 29-year-old Denise Huskins from her Kirkland Avenue residence on Mare Island on March 23.

The Federal Bureau of Investigation obtained a warrant for the arrest of Muller, and the case remains an active, ongoing investigation by the FBI, the Vallejo Police Department, and Alameda County Sheriff’s Department, the FBI said.

At about 2 p.m. on March 23, 30-year-old physical therapist Aaron Quinn called police to report that his girlfriend was violently abducted from their home in the middle of the night and that the kidnappers demanded an $8,500 ransom.

In a statement from the FBI, Huskins was ordered to bind Quinn with zip ties and then told to go into the bedroom closet.

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SUSPECT BACKGROUND

The man arrested for the kidnapping of a Vallejo woman was a teacher at Harvard Law School from 2006-2009, according to an FBI affidavit.

In June, Muller told sheriff detectives in an interview he is a former Marine, who also attended Harvard from 2003-2006 before teaching at Harvard.

Muller had been admitted to the California Bar in 2011, but was disbarred in 2015, according to the affidavit. Muller also told detectives he suffered from Gulf War Illness, psychosis, and was diagnosed with Bipolar Disorder in 2008. He was transported to a hospital in South Lake Tahoe.

Authorities eventually caught up with Muller in South Lake Tahoe in June, after tracking down a cell he left behind in an attempted home invasion robbery in Dublin.

And he even was a suspect in 2009 home invasions in Palo Alto and Mountain View, and police pointed out several similarities in the two home invasions. Both victims were women, similar in age, and they happened in the early morning, police said. And both women were blindfolded and restrained by the suspect, similar to what happened to Huskins, according to the investigators.

Click here for more of his background, and how the two cases are related.