Matt Linton, a senior software engineer at Google, says he was asked to leave Caesars Palace hotel in Las Vegas Thursday night after a tweet about hacking was reported to the Las Vegas Metropolitan Police Department. The police have confirmed that Linton is not considered a threat, but until Friday afternoon the engineer said he was not let back into Caesars, which is hosting Defcon, the annual conference that attracts thousands of security researchers, academics, lawyers, and hackers.1 The incident highlights the high level of security precautions being taken in the city less than a year after a mass shooting at the nearby Mandalay Bay Hotel, when a gunman killed 58 people and injured hundreds of others.

Linton sent the tweet on Wednesday night in response to another user's thread about the Defcon Wi-Fi network, which is notorious for being insecure due to the number of hackers who attend the conference. The original tweet argued that the network might be more secure than people think, since so many users are on it simultaneously. In other words, there are so many possible victims that it's easy to hide in a crowd. Linton responded that it might be more fruitful, theoretically, to "attack" the wealthy attendees of BlackHat, a more commercial cybersecurity conference that takes place right before Defcon. Linton was a speaker at BlackHat this year.

The short conversation was about the many ways a person's device might be compromised during the biggest week of the year for hackers. But at the time, Linton was replying to a protected account, meaning people could not view the original tweet if they didn't already follow that user on Twitter. (The user made their tweets public on Friday.) For most people, Linton's tweet—which began "If I had the time, budget, and motive to launch really good attacks in Vegas, I would…"—would appear without any other context.

"We saw the comment on social media, it was brought to our attention by the private sector. We have a lot of concerns when someone uses the word attack," says Jim Seebock, a captain at the Las Vegas Metropolitan Police Department.

Linton says the police got his contact information from Caesars, and then reached him on his cellphone.

"LVPD interviewed me and I believe I had cleared it up with them satisfactorily when they liked and retweeted my second clarification tweet about how 'attack' means 'hack a cell phone' when you're at Defcon," Linton said in a Twitter direct message. (As of Friday afternoon, the police department's official twitter account did not appear to have liked or retweeted Linton's messages.)

Seebock confirmed that Linton has since been cleared as a threat, and the engineer is facing no charges. But when Linton returned to his hotel room around midnight Thursday, he discovered that he could not use his keycard to access it. He says he was then asked to leave the hotel, and that he was still charged half the price he paid for his room Thursday night. Caesars did not immediately respond to a request for comment.