Dominic Monaghan's Stalker Busted for Death Threats

Dominic Monaghan's alleged stalker is behind bars after cops say she sent threatening messages to the actor, even after he got a restraining order against her.

Law enforcement sources tell TMZ ... Meredith McLarty's been harassing Monaghan since 2014. The actor was granted a restraining order against her last year, but cops say she kept trying to get in touch with him. She eventually referenced John Lennon's assassin ... tweeting, "Three words ...Mark David Chapman."

Cops got an arrest warrant and nabbed McLarty last week at LAX.