Dina Lohan: Lindsay Is Not a Bad Influence on Her Sister

Dina Lohan is furious that her ex-husband Michael brought the Los Angeles Country Sheriff's Department to daughter Lindsay's apartment Thursday – and disputes his claim that the starlet is a bad influence on her younger sister, Ali.

"They scared the hell out of my girls," Dina tells PEOPLE. "Ali called me hysterically crying. They were hysterical and petrified of him. I spoke to the [police officer] and said, 'You don’t have a warrant, get out!'

Michael says he called the cops to perform a "welfare check" on daughter Ali, 16, because he was concerned about her safety. "Ali is being exposed to nightlife and the people Lindsay is surrounding herself with," he told Hollyscoop at the time. She's 16 and she doesn't belong there. She's a minor."

But Dina says Ali and Lindsay, 23, are perfectly safe.

"Lindsay is absolutely, 100 percent, not [a bad influence]," she says. "Ali is amazing. She loves her sister. Would I let my daughter go anywhere that's dangerous? I mean, come on, Ali and Lindsay need to be protected from their ex-father. That's the dangerous situation."

Though Michael says he wants to help his daughters, Dina thinks that by going public with his concerns, "he's creating a worse situation for everyone."

"Michael's not well," Dina says. "Nothing he does surprises me. He's dangerous. He's not going to be able to [intrude] again and get that close. Ali doesn't want to see him again. She has a block on her phone because she was so petrified of him"

Bottom line? "He needs to pay child support and leave his kids alone," Dina says. "I'm not going to sit idle and watch bad things happen to my kids."