New 'Joker' Massacre Thwarted By Maryland Cops It has been one week since Aurora, Colorado's movie theater massacre.

July 27, 2012  -- One week after Colorado's movie theater shooting, Maryland cops arrested a heavily armed man who told his employer he was a "joker" who was going to "blow everybody up."

Police said today they believe they "thwarted a massacre."

The suspect, identified as Neil Edwin Prescott in a court document obtained by ABC News, was being dismissed from his job. He made threatening statements to his supervisor at least twice on Monday, police said.

Prescott had an arsenal of about 25 firearms at his residence, including semi-automatic rifles, shotguns and handguns, according to a police affidavit. Police said he also had high powered scopes and magazines and thousands of rounds of ammunition in "40 large steel boxes."

He was quoted as telling his employer, "I am a joker, I'm going to load my guns and blow everybody up," police said.

"It is clear that the comments made by Prescott reference a recent mass murder which occurred in Colorado within the last several days in which the alleged shooter called himself the Joker, died [sic] his hair red and shot up a movie theater containing men, women and children and showing the 'The Dark Night Rises,'" according to the court document.

"Prescott also stated that he would like to see the supervisor's brain splatter all over the sidewalk," the document said.

Prescott allegedly acknowledged to his employer that he should not be making these statements over the phone, saying, "It's kind of foolish of me to say this kind of things [sic] over government phone."

"In light of what happened a week ago in Aurora, Colorado, it's important to know that we take all threats seriously and if you're going to make a threat, we will take action," Prince George's County Chief Mark Magaw said at a news conference today.

When police arrived at Prescott's house on Thursday to speak to him, he was wearing a t-shirt with the writing, "Guns don't kill people, I do."

He was taken into custody based on an emergency petition for medical treatment, police said. Authorities said Prescott's demeanor was "very quiet" when he was taken into custody and that he was cooperative.

Law enforcement sources tell ABC News that he is from Crofton, Md.

The man was facing termination from his job with a company doing contract work for Pitney Bowes, a leading company in producing postage meters and machines.

The company released the following statement: "The suspect arrested is an employee of a subcontractor to Pitney Bowes. At Pitney Bowes we have clear security protocol and when we had concerns about this individual, we contacted authorities."

The Prince George Police Department declined to comment, but said they will be sharing more information at a 1 p.m. news conference.

On July 20, shooting suspect James Holmes allegedly opened fire in an Aurora, Colo., movie theater during a midnight showing of the new Batman movie, "The Dark Knight Rises." Twelve people were killed and 58 were wounded.

Holmes told police he was The Joker, a villain in the Batman movies, police said.