Michael Lohan insists his rehab-prone daughter, Lindsay, is back on the booze, and the talkative celebrity dad blames one person for Lindsay’s tumble off the wagon-LiLo’s rumored girlfriend, DJ Samantha Ronson.

“I’ve been up and down the road (in discussions) with my ex-wife (Dina) and it’s to the point now that I’m going to confront Samantha and Jenny Muro (Lindsay’s production assistant) myself,” Michael said in an interview with MSNBC late Tuesday.

Michael even makes the sensational allegation that Sam “slips” drinks to Lindsay.

“Samantha drinks and passes the drinks under the table to Lindsay, and behind the scenes it gets worse and worse,” Michael says. “Sam is using my daughter. My daughter isn’t working because she’s always with Sam. Even my ex-wife knows it. She just isn’t doing anything about it.”

Way to reconnect with your estranged daughter, Michael.

“This is totally a lie and untrue,” Lindsay’s rep says of Michael’s relapse claim.