How a registered sex offender wound up living in an Airbnb hosting unsuspecting guests

• A concerned citizen tried to alert Airbnb that a known registered sex offender was living in a house being rented out on the platform.
• But this offender, although registered, was not listed in the public sex offenders database.
• The situation raises questions about the safety checks Airbnb - and other companies- can do.
• It also serves as a warning that the public sex offender database is an imperfect source of information.

To most people, the term "registered sex offender" makes them think of a convicted rapist who has been released from prison, whose location is now visible in a database for all.

Each US state maintains this public database on the internet, sometimes referred to as the Megan's Law database.

But what most people don't know is that it's possible for someone to be a registered sex offender and not be found anywhere on it.

That means that the person won't show up when a concerned citizen is searching for sex offenders by zip code. They also won't show up if a search is done by the person's name or address, and they won't be visible when the database is used for a background check by a potential employer, experts say.

And that's how an infamous registered sex offender in the upscale community of Carmel Valley, California, wound up living as a host in an Airbnb, regularly entertaining guests - even though Airbnb was notified about his history by at least one person who recognized him, according to documents seen by Business Insider.

The situation points to a frightening idea: that Airbnb may not always be aware of all the people living in the homes rented out on its platform, or the people who have access to them, and wouldn't have done its typical safety checks on them.

Shh, don't tell Airbnb

There were a lot of people who recognized this man. His name is Carl Bergstrom, a former wealthy "concierge" doctor in the area whose sensational and lurid 2009 rape trial in the sleepy community of Carmel, California, was closely covered by the local media.

Although the community knew his history, it was very difficult for Airbnb to know it. For one thing, he wasn't listed as the Airbnb host.

The home was listed by the woman he lived with, "Sharon" a little over a year ago, and her host rating was high. And, like many people in Carmel, Sharon knew of Bergstrom's background.

"Carl is not on Megan's list or my Airbnb so someone must have pointed us out to you?" she told us when we asked if she had told Airbnb that Bergstrom was living there.

"People know Carl lives there, but the public doesn't know," one person who lives in the area told us. "They [Airbnb] won't allow you to rent if you are registered sex offender, but what if someone is living in your house? I don't think people are aware that people can be a registered sex offender but not disclosed."

When Business Insider contacted Airbnb with questions about what it knew about Bergstrom living in the house, and how it knows to perform background checks on other adults in a house if the host doesn't disclose them, Airbnb didn't answer our questions directly.

It did, however, tell us that as a result of our inquiry, it had banned Sharon and her Carmel Valley home from its platform.

"Hosts need to be transparent about who has access to their home (so we can check) and not doing so can lead to removal like in this case. We removed this host and this listing from our community," said Nick Shapiro, Airbnb's Global Head of Trust & Risk Management.

The lurid rape trial of the concierge doctor

Before his arrest in 2009, Bergstrom was known in the community as a wealthy "concierge" doctor in the area whose patients paid to keep him on a full-time retainer.

On the night that landed him in prison, he met up with a woman at a bar, according to trial testimony.

They drank a lot and went back to his place where she passed out, she testified. She alleges that she woke up to him assaulting her. Bergstrom maintained his innocence at trial, saying that the sex was consensual.

The woman called 911 that night and the Carmel police found her on the curb outside his house at about 3 a.m. crying hysterically.

At trial, prosecutors presented two other women who also accused him of other incidents, although neither had previously filed charges. Both women testified they thought they may have been drugged. Prosecutors also presented evidence that Bergstrom sold cocaine and Bergstrom admitted at trial that he had traded prescription drugs for cocaine.

The case delved into many lurid details about his lifestyle and sexual proclivities and captured the public's attention. A jury convicted him of the charge of felony "forcible sodomy" and sentenced him to six years in prison.

After conviction, he gave up his license to practice medicine, just as governing bodies had taken steps to revoke it, according to news reports at the time.

While in prison, he appealed his case. The appellate court overturned the verdict, finding the judge had given poor jury instructions on how to decide Bergstrom's guilt. The appellate court didn't declare that he was innocent. It authorized a new trial.

But there were reasons why a second trial would be hard to pull off, including that the victim didn't want to go through the whole ordeal again, according to news reports. Instead, the district attorney struck a plea deal with Bergstrom. He agreed to plead no contest to a lessor charge of felony sexual battery, according to news reports and court records seen by Business Insider. He was ordered to pay fines and restitution and he was released from prison for time served.

As part of the plea, Bergstrom agreed to be a registered sex offender for life. Commander Johnathan Thornburg of the Monterey County Sheriff's department confirmed to Business Insider that "he is currently registered."

But here's the catch: his plea was for an offense allowed to be excluded from the public database.

When Business Insider contacted the Monterey County District Attorney office to ask about the exclusion, the assistant district attorney we spoke to seemed surprised.

The assistant DA told us he thought Bergstrom "should be" in the database, and actually checked it himself while we were on the phone. But he's not. Not by name. Not by address.

Although this attorney had prosecuted other sexual assault cases and said he was "familiar" with Bergstrom's case, he told us he didn't work on it himself.

He told us that sometimes prosecutors strike plea deals and that he wasn't familiar enough with the sexual battery statues that covered this particular deal.

Business Insider asked Bergstrom to contact us and comment on this story through our communications with "Sharon" but he did not respond.

Registered but not revealed

All of this explains why Bergstrom's past may have gone unnoticed by Airbnb, even if people in the Carmel community alerted the company to his presence in the house.

Most states have rules that allow some convicted offenders to be excluded from the public database, says Amber Widgery, Senior Policy Specialist for the Criminal Justice Program at the National Conference of State Legislatures.

For the most part, the people excluded are considered low risk to the public. They may have been convicted of a misdemeanor, for instance.

Or they may be excluded so as not to expose the address, and/or identity of the victim. One example is an offense committed against a child by a relative who still lives with the child, like a parent, sibling, aunt/uncle or grandparent, according to the application for exclusion, California Penal Code 290.46. That circumstance only applies to offenses that didn't involve a substantial incident with the child.

Excluded by not invisible

The upshot is that there are registered sex offenders excluded from the public database for all sorts of reasons.

And this makes it harder, though not impossible, for community/sharing-economy startups such as Airbnb to detect them, even when they routinely do background checks.

In Airbnb's case, it remains unclear how the company discovers and checks on other adults living in a home besides the host if the host hasn't notified the company.

Airbnb's publicly available policies about background checks do not discuss its requirements about roommates, spouses or others who have access to the house.

Airbnb's Shapiro did say the company uses technology to watch for "signals" that may indicate something unsafe is going on but he declined say if one of those signals would alert the company to additional adults who have moved in with a host and be in need of a background check.

On the other hand, it may be comforting to know that the public sex offenders database isn't the only source for a background check, even for sexual offenses.

If a person has been convicted of a felony offense, that information can still be uncovered by doing a more thorough, formal background check that includes a search of state criminal records.

Airbnb's Shapiro tells us that for all US residents who apply to be a host and who have been disclosed to Airbnb, the company does do such "background checks looking for prior felony convictions, sex offender registrations, or significant misdemeanors. We are working with additional governments around the world to identify where we can do more background checks."

He adds, "more than 200 million guests have had safe, positive experiences on Airbnb."

In the meantime, for concerned Airbnb users, it doesn't hurt to ask your next host about the other people who will be in the home with you, just as the Airbnb host has a right to ask you about the people you'll be bringing into their home.