AceShowbiz -

Someone is not happy about Christina Applegate's relationship with her fiance of two years, Martyn LeNoble. 43-year-old Marty was blackmailed by an unknown mad man on Twitter. According to TMZ, LAPD has been investigating the case, while apparently the disturbing tweets have been removed from his Twitter.

On September 20, Christina's secret admirer furiously tweeted Martyn, "You stole [Christina] away from me. If not for you she would be mine." The fan went on, "I will not accept this. I am going to kill you!!!!!!!!!"

The unrecognized Twitter user then sent another serious violent threat, "I'm going to bust your head in for taking her away from me!!! Be afraid, be very afraid!!" The stalker also wrote, "You think this is a joke? I want to see how funny you think I am when I blow your f**king head off!!!"

Marty, the Dutch bassist of Porno For Pyros, couldn't identify the Twitter user. Though the profile has been deleted, LAPD is still trying to find out the true identity of the stalker by tracking Twitter's records. So far, neither Christina nor Martyn made any personal comments on the incident.

The 40-year-old dubbing artist of "Alvin and the Chipmunks: Chip-Wrecked" and the 43-year-old punk rock bassist have been together for four years and had never received such blackmails before. They were engaged on 2010 Valentine's Day, and have an almost 2-year-old daughter named Sadie Grace LeNoble.