WASHINGTON — To his friends, Neil E. Prescott is a "gentle giant" — a physically towering young man with a background in computers and electronics and a sarcastic, even biting, sense of humor that people close to him knew to shrug off as innocuous.

But police say they had no choice but to take it seriously when Prescott threatened to shoot up his workplace and referred to himself as "a joker," comments that raised particular alarm in the wake of last week's mass shooting at a Colorado theater during the latest Batman movie. The man accused in the Colorado shootings dyed his hair reddish-orange, and New York Police Commissioner Ray Kelly has said the man called himself the Joker — a reference to Batman's nemesis.

Prescott was taken into custody early Friday at his apartment in Maryland, where officers found several thousand rounds of ammunition and a cache of about two dozen weapons including semi-automatic rifles and pistols. He was receiving an emergency psychiatric evaluation at a hospital and had not been charged as of Saturday afternoon.

Two friends told The Associated Press Saturday that they couldn't imagine that Prescott, who was in the process of being fired or already had lost his job, intended to be taken seriously when he allegedly told a supervisor: "I'm a joker and I'm gonna load my guns and blow everybody up."

"Neil's the kind of guy who had the ability to say the wrong thing at the wrong time and not mean anything by it. So to him, he thinks it's funny. He's kind of a joker," said Wesley Weber, who said his friend, at 6 feet 7 inches, is a "gentle giant" prone to bouts of exaggeration who "talked big but didn't walk the walk."

Prescott is "no stranger to sarcasm regardless of political correctness," and is fond of T-shirts with sarcastic, provocative or even inflammatory remarks, said another friend Mike Cochran. When first approached by officers, police say, Prescott was wearing a shirt that said "Guns don't kill people. I do."

Friends say that over the years, Prescott had been interested in hobbies such as computers, electronics and ham radios.

In recent years, though, he'd cultivated a passion for collecting firearms. He'd practice his shot at the training range, friends said, and communicate online with fellow gun enthusiasts about the ins and outs of firearm equipment and gun laws.

Police say Prescott, an employee of a subcontractor for software and mailroom supplier Pitney Bowes, made the threats during two Monday morning phone conversations with a supervisor. The supervisor, who declined to comment Saturday to a reporter who showed up at his house, said the comments made him fear for his life and that he was aware of Prescott's weapons' cache.

Prescott at one point said he wished to see his supervisor's "brain splatter all over the sidewalk," but also acknowledged that he shouldn't be saying such things over the phone, according to an application in support of a search warrant.

Weber said that while he didn't know the exact context of the threat, he thought it was the kind of comment that is taken more seriously now than it may have been years ago, especially one week after the Colorado shooting.