Image caption This police photo shows the guns found in possession of the suspect

A heavily armed man who called himself a "joker" has been arrested after threatening his employer in the US state of Maryland, police say.

Neil Prescott, 28, allegedly said he was going to "load my guns and blow everybody up" at his workplace.

Wearing a t-shirt that read "guns don't kill people. I do" when arrested, he was in the process of being fired.

The suspect in last week's massacre at a Colorado Batman screening reportedly told police he was The Joker.

Mark Magaw, police chief of Prince George's County in Maryland, told reporters they were taking "all threats seriously" in light of last Friday's shootings.

"If you're going to make a threat, we will take action," he said.

'Very quiet'

Mr Prescott had several thousand rounds of ammunition and about two dozen firearms in his apartment when it was searched by the authorities on Friday morning.

Police said he was "very quiet" and co-operative when arrested at his home in Crofton, near Annapolis.

He allegedly made multiple threats this week, including telling a supervisor at the mailroom supplier where he worked that he wanted to see his "brain splatter on the floor".

Mr Prescott was receiving a mental health evaluation with charges pending.

Meanwhile, a defence motion filed on Friday says that James Holmes, the suspect in the Colorado shooting, was being treated by a psychiatrist at the university where he studied.

On Friday in Colorado more than 1,000 people attended the funeral of Micayla Medek, one of the 12 victims of last week's shooting.

The 23-year-old was a student who had gone to the movie with a group of friends.

A full military funeral is scheduled next Friday for Jonathan Blunk, a navy veteran.