Michael Lohan's girlfriend claims he's threatening her with a knife and threatening to take their infant son -- and now police are on scene ... TMZ has learned.
Kate Major blasted Lohan on Twitter Monday evening ... claiming she had to lock herself and their one-year-old son Landon in a bedroom while a knife-wielding Lohan tried to break down the door.
Threatening to take our son. What judge would rule for. him??? Stuck inside a house with this guy? He has a knife
— Kate Major (@k8major) February 18, 2014
Cops in Boca Raton, FL tell us officers have responded to their house ... and are talking to Michael and Kate right now.
Sources close to the couple tell us Michael is the one who called 911 when Kate started acting erratically ... and locked herself in the room.
We're told officers want one of them to leave the house immediately -- but Michael isn't budging because he thinks Kate is drunk ... and doesn't want to leave her with the baby.
We just spoke to Michael who claims Kate's been drinking again ... and it got so bad she tried to kill herself over the weekend. Lohan tells us he's worried about the welfare of their child and says he'll attempt to get custody of their son if she doesn't get help.
During Kate's twitter rant ... she addressed the suicide saying, "Someone trying to kill u is worse than trying to kill yourself ! #udontscareme."
Kate also vowed to never let Michael take their son away from her.
Update 7:25 PM PT -- Police have left the house. No arrests were made ... so, should be a fun night at the Lohan corral.
Michael Lohan's Baby Mama -- He Threatened to Stab Me ... 'I'm Gonna Kill You Bitch'
Update 11:20 A.M. PT -- Kate just told TMZ she lied about the threats, saying "I regretfully tweeted while my emotions were high that I was being threatened by Michael with a knife, this was not the case." Major tells us she made it up because she feared Michael would take her son away.
Michael Lohan went ballistic and brandished a knife last night during his fight with baby mama Kate Major saying, "I'm going to kill you, bitch!" -- at least that's what Kate told cops -- but Michael's 911 call tells a different story.
TMZ has obtained the police report regarding the altercation last night at Michael's Florida house ... after Michael called 911, claiming Kate was drunk and acting erratically around their one-year-old son.
According to the report, when police arrived, Kate told them Michael had falsely accused her of drinking around their baby and a fight broke out. That's when Kate claims Michael grabbed a knife and threatened to kill her with it.
Kate told police she locked herself in a bedroom to get away from him ... and he tried to kick the door down. When he failed, Kate claims Michael went outside to the bedroom's sliding glass doors and made stabbing gestures at her.
Kate claims she tried to call police ... but her phone was broken ... even though she still managed to send out a bunch of tweets.
Police spoke to Michael too -- he denied threatening Kate in any way -- and his 911 call paints a very calm and calculating picture ... almost like he and Kate have lots and lots of experience calling 911 on each other.
Audio at TMZ