(CNN) -- A Maryland man who was in the process of being fired was taken into custody Friday after allegedly calling himself a "joker" and threatening a supervisor, police said.
Police in the counties of Prince George's and Anne Arundel acted on the alleged threat and the use of the word "joker." The Joker is the nemesis of the comic character Batman and a character in the film "The Dark Knight."
Police say the suspect in last Friday's shooting inside a movie theater in Aurora, Colorado, where the film was being shown, identified himself afterward to police as "the Joker." James Holmes has been arrested in the shooting, in which 12 people were killed and scores more wounded.
"An individual who was in the process of being fired was involved in two separate conversations with his supervisor," Prince George's County Police Chief Mark Magaw told reporters. "Both of those times and both of those telephone conversations he made significant threats to coming back and harming people at the business."
Magaw added, "In fact, he said 'I'm a joker and I'm gonna load my guns and blow everyone up.'"
Magaw said that, in light of the Aurora incident, "it's important (for) the community to know that we take all threats seriously and if you're going to make a threat, we will take action."
Magaw said police went Thursday afternoon to the man's apartment in Crofton to interview him and found him wearing a T-shirt that said, "Guns don't kill people. I do."
Later in the day, a district court judge issued a court order for the man to be held on an emergency commitment.
Early Friday, police picked him up from his apartment and took him to Anne Arundel County Medical Center, where he was being given a mental health evaluation, Magaw said. "Our first and immediate responsibility was to get him mental help, if that was what he needed," he said.
A search of the man's apartment yielded 25 guns and thousands of rounds of ammunition, he said.
"We believe this was a significant threat based on some of the mental issues this individual has, the weapon capability he had (and) what he said to the employees at Pitney Bowes," Magaw said, referring to the business involved.
Pitney Bowes issued a statement Friday saying the man was an employee of a subcontractor for the company and "has not been on any Pitney Bowes property in more than four months." Pitney Bowes makes postage meters and scales and other products.
Magaw said that, given Pitney Bowes' status as a federal contractor, the man could be subject to federal charges. Charges are being reviewed and may be filed over the weekend, Magaw said.