Holy dysfunctional family! Lindsay Lohan's dad, Michael, just showed up at her apartment with cops in tow, saying he was concerned about his 16-year-old daughter, Ali.

TMZ reports that Michael convinced police to accompany him on a "welfare check" after he said he was concerned that the two sisters went to last weekend's Coachella Music Festival outside Palm Springs, Calif., and Lindsay drove them home at speeds exceeding 100 mph.

Lindsay began tweeting when the incident happened, saying, "I have no choice but to make this public, due to my sister's safety, as well as my own, 'my ex-dad' just WALKED INTO MY APT like the devil's ... advocate with officers." She continued, "Let's not forget, that my father KIDNAPPED me from a COURT ROOM when I was 4 years old and is CRAZY! He has NEVER paid child support, and is marrying a tabloid writer and can barely spell his own name due to his 'brain' that has been ruined due to HIS drug use .... When will it ever end .... It's been going on my whole life with him -- hasn't he caused enough pain? Thank g-d for my mommy ... w/out her, I wouldn't even know myself ...."

Michael Lohan told Hollyscoop, "I went to the police department concerned about Ali's welfare. I wanted to check on Ali. I want to make sure she's OK. She's 16 and she doesn't belong there! She's a minor. I just want to make sure she's OK .... Ali is being exposed to nightlife and the people Lindsay is surrounding herself with."

Lindsay's mom, Dina, told TMZ, "I was told by my attorneys not to speak because it is very serious and my ex could be in big trouble. He's dangerous. If he can't get to them he is going to try to hurt them -- it's not good."