Dina Lohan claims Lindsay had romance with Heath Ledger at time of his death

In yet another of Radar’s sordid exclusives, Lindsay Lohan’s mother, Dina, reveals to her dad that Lindsay was secretly dating Heath Ledger at the time of his death in January of 2008.

“She was dating Heath when he died,” Dina tells Michael Lohan. “I don’t know if you know that, but I know because I would drop her off and they were friends – Very, very close…okay?”

In another of Michael Lohan’s secret phone recordings his ex-wife explains that she’s telling him this because she’s afraid that Lindsay could end up just like Heath.

“Because when she’s drunk or takes an Adderall with booze, she could do something like Heath Ledger did, in a second…without thinking,” Dina explains.

Adderall is an amphetamine-based medication used to treat ADHD. It is both highly addictive, and can cause fatal heart problems.

“She cannot be alone. When she sleeps here, she sleeps with me,” Mommy Lohan continues, then finds a new way to slide in the knife, “She has fears from her childhood…and what you did to us.”

The pair’s bitter divorce in 2007 is often used by Dina to excuse Lindsay’s problems, but Momma’s biggest concern on this call is her daughter’s turbulent fling with ex-girlfriend, Sam Ronson.

“It’s very easy for a rational person to say, walk away. But for an irrational person who has a problem with her DNA, alcohol and Adderall and asthma and every other thing she’s got wrong with her….”

And there we see further proof that the most dangerous drug is an enabling parent.

The tape ends just there, but there’s much more to come — you can all bet on that…