On Tuesday morning, a 24-year old man from San Diego caused a social media uproar by tweeting a selfie in front of a Santee gun store. The caption read "Waiting for the shop to open so I can buy that new UZI for coachella 2018."

Following a mass shooting at a country music festival in Las Vegas the previous Sunday, which killed 59 people and injured about 500, many people have expressed concerns about security for upcoming festivals.

The threatening tweet was sent out by electronic music producer Nickyxplicit, whose Facebook profile identified him as Nick Braun, resident of San Diego.

In a few hours, the tweet began garnering attention on social media. Then, a photo posted by the Discount Gun Mart in Santee, where the selfie was taken, sparked rumors that Braun had been arrested.

"We investigate these things thoroughly," said Ryan Keim, Public Affairs Director at the San Diego County Sheriff's Department. "This apparently didn't meet the criteria for a crime."

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According to Keim, for a threat like this to constitute a crime, there needs to be a realistic chance that the suspect will actually be able to carry it out. In this case, the Sheriff's Department did not believe this to be the case.

"We determined it wasn't a crime, but a mental health issue," Keim said.

This was not the first time Braun posted threatening messages online. A few hours earlier, Braun had sent out several tweets threatening to shoot up a festival before committing suicide and saying he'd appreciate someone bringing a grenade to a (music) venue.

Braun's account offered a variety of racist and misogynist tweets before it was suspended Wednesday afternoon.

Of those who have interacted with Braun online, many have expressed concerns about his determination to turn his social media threats into reality.

Levi Martin, who is also a music producer based out of San Diego, claims that after repeated harassment online, Braun showed up at his family's apartment one night.

"He tried to walk into my grandpa's apt, without anyone answering the door," Martin said in a Facebook message. "But luckily my mom was there and woke me up, so I rushed out and he ran away without him saying a word to me."

After seeing Braun's most recent threat on social media, Martin said he alerted the authorities, and so did plenty of other Twitter users.

State laws regarding individuals with mental health issues did not allow the San Diego Sheriff's Department to release any further information on the case, Keim said, once their investigation had determined that Braun's threat did not meet the criteria for a crime.

Braun's Twitter account has been suspended as of Wednesday afternoon.

Those who have experienced Braun's harassment firsthand are concerned there was no arrest following Tuesday's threat.

"If something doesn't get done, he is going to hurt a lot of people. It's going to be his face on one of these mass shootings," Tyler Burrett, an electronic music producer from Los Angeles, said in a Facebook message.

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