A panicked cinema audience at a movie theatre in Long Beach, California, fled a screening on Saturday night according to reports.
The Long Beach Post said that police were called to the Regal Edwards Theater after a 'suspicious male adult' entered the screening with a backpack, and began looking out over the crowd near one of the emergency exits.
Long Beach Police said that it received reports of shots coming from inside the cinema, but on arriving found that the man was unarmed.
However, he was detained and then arrested on an unrelated outstanding warrant.
A statement from the LBPD released on Facebook read: “This evening the #LBPD received calls reporting shots coming from inside the Edwards theater.
“Officers were on scene within a minute of dispatch & discovered patrons had self-evacuated due to a suspicious male adult who was wearing a backpack and looking out at the crowd near an emergency exit inside the theater.
“The suspect was detained and was not found in possession of any weapons, however he was taken into custody for an unrelated outstanding warrant.”
In a separate incident in Chicago, police were called and two men were taken away in handcuffs after they talked loudly throughout the movie, smoked and even blew smoke in other cinema-goers faces, according to Fox News.
Another screening of the movie in Huntingdon Beach, California, was also closed down last Thursday after police received a 'credible threat', though it re-opened the next day.
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It's followed concerns that the movie, which centres on Joaquin Phoenix's Arthur Fleck, a failed comedian who becomes an violent, angry loner, could inspire instances of real-life violence following the continued spate mass shootings in the US.
The New York Police Department even stepped up security by dispatching undercover officers to some screenings of the movie, as well as visibly stationing officers at movie theatres.
Meanwhile, safety emails were reportedly sent out to military personnel, reminding off duty servicemen and women what to do should a violent incident unfold, said to have been sent out due to information received by the FBI over 'disturbing and very specific chatter in the dark web'.
“If you’re stuck, hide (also known as ‘sheltering in place’), and stay quiet,” read the email. “If a shooter finds you, fight with whatever you can.”
Joker actor Marc Maron has slated recent media attention to the film, however, suggesting it could even ‘provoke violence’.