The alleged stalker, Meredith McLarty, has reportedly been harassing Monaghan since 2014 and invoked John Lennon's murder in a threat on the Lord of the Rings' actor's life. Monaghan got a restraining order against McLarty in 2015, after she reportedly tweeted, "Three words ...Mark David Chapman..." and "#domswildthings," according to police. Chapman is a reference to the man who murdered the famous Beatle in 1980. (The tweet is from March 2015, but just became public thanks to legal documents obtained by TMZ.)
McLarty reportedly ignored the restraining order and continued to harass Monaghan online. She's currently on the run, with cops looking for her to serve a warrant for her arrest.