A 37-year-old Seattle man, who allegedly threatened a community mosque online, was arrested on Wednesday (14 June) following a brief standoff with police. The man, who was not identified, reportedly posted that he had purchased ammunition and an assault rifle, just days after the deadly attack at an Orlando nightclub on 12 June.

The Seattle Times reported authorities were alerted of the threats by one of the man's out-of-state friends. Police arrived at the suspect's apartment on Greenwood Avenue North, where a brief standoff ensued. Authorities took the man into custody around 3.30pm PDT. No injures were reported, according to the Times.

"We take this very seriously," Captain Sean O'Donell said. "We are very aware of the situation in Orlando and we are taking steps to ensure the safety of the individuals at the mosque...we received information and acted on it immediately out of an abundance of caution."

Police warned Hisham Farajallah, spokesman at the Idris Mosque in Northgate, that his place of worship was the man's target. Law enforcement was stationed outside the mosque later on Wednesday (14 June). "We are prepared. The best we can do is inform people," Farajallah told the Times. He noted that some mosque members were fearful and have been told to remain vigilant.

The suspect had been previously contacted by local police as they investigated harassment and threats made to a different mosque. Redmond police reportedly received anonymous calls with threats towards women and children worshipers at a Redmond mosque following the Orlando nightclub shooting, which left 49 dead and 53 injured.

According to MyNorthwest.com, an anonymous caller threatened the Muslim Association of Puget Sound mosque on Tuesday (12 June). KIRO reported that there were approximately 350 people praying inside the mosque when the threats were called in. The caller mentioned an activity that was being held at the mosque later that night.

"We are coordinating closely with MAPs (Muslim Association of Puget Sound) staff, who also increased security and notified their congregation of the anonymous threat," Redmond Police said at the time. Redmond Mayor John Marchione then visited the mosque on 13 June.

In a statement, Seattle police said it was working closely with the FBI to investigate "the rapidly developing case". MyNorthwest.com reported the suspect, who is under investigation for malicious harassment, is expected to be booked into King County Jail.