( 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 . Movie massacre : 'Oh my God , this is really happening ' `` 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 gon na 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 do n'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 . Colorado shooting suspect was a psychiatric patient . Opinion : Why the media can not ignore the killer . Court appearance fuels theories about Colorado shooting suspect .
NEW : ` ` Guns do n't kill people . I do , '' says the man 's T - shirt , according to police . Incident comes in the wake of last Friday 's massacre in Denver , Colorado . The gun was in the process of being fired , police said . The man calls himself a ` ` joker , '' police said .