I thought it seemed odd that Heath Ledger would have been staying at Mary-Kate Olsen's apartment, as was first reported after his death. Then came the news that Mary-Kate was the first person called when Heath's housekeeper discovered his body. Now, it turns out Heath and the young twin were dating:

"Mary-Kate and Heath were casually dating for three months before Heath's death," a source has told PEOPLE. "They were hooking up, but neither were particularly interested in making it exclusive."

As for what drew the two together, says the source, "They had a bond that was based on partying, and they had the same tastes in partying ... like, in terms of where they liked to hang out in New York, what time they would want to go out. They just had the same sensibility."

The "non-exclusive" bit explains why Heath was most recently tied to Aussie supermodel Gemma Ward, rather than Mary-Kate. And why Helena Christensen (another model romantically linked to Heath, though Helena calls them just "friends") was on her way over to his house when he died.

Meanwhile, as Heath's family assures the public that Heath was not suicidal, a doctor tells the NY Post that Heath's death was unlikely to be accidental. Sad. Let's hope he's wrong.

The cause of Heath Ledger's death is still inconclusive following this morning's autopsy analysis. We will have to wait a couple weeks for toxicology reports to confirm whether drugs are to blame.

Sadly, the overdose theory grows stronger. In addition to finding bottles of Valium, Zoloft, and the sleep-aid Ambien in Heath's apartment, police recovered a $20 bill tainted with narcotic residue (cocaine?), and several drug packets of an unknown substance.

While we don't know that Heath ingested all (or any) of these substances yesterday, he had been struggling with drug abuse for a while, according to reports from a close friend:

"This is terrible and I'm in shock. But to tell you the truth... we saw it coming. Heath has gone though a rough road of trying to get sober. Things were very dark."

Heath's "dark" phase may relate to his "Joker" performance in this year's aptly titled "Dark Knight", in which his performance is hailed "pitch-perfect". The actor told The NY Times that playing the "psychopathic, mass-murdering, schizophrenic clown with zero empathy" was "physically and mentally draining."

"Last week I probably slept an average of two hours a night," he said. "I couldn't stop thinking. My body was exhausted, and my mind was still going."

It's not unusual to adopt the emotional state of your character as part of "method acting" - a style probably used by Heath. Gwyneth Paltrow, for instance, became so consumed by her harrowing portrayal of Sylvia Plath in "Sylvia" that she began to dream and think like her troubled character.

Similarly, Heath reportedly prepared for "the joker" by living "alone in a hotel room for a month researching the character and developing his performance, which he claims is based upon Sid Vicious and the character of Alex in A Clockwork Orange."

Ummm... in case you haven't seen A Clockwork Orange, I can personally confirm that "Alex" is only THE darkest and most sincerely disturbed character of all time. It makes sense that anyone would be depressed after adopting that mental state. Add to that a heartbreaking split with the mother of your child, depressive drugs...

Still, it seems that Heath did not intend to commit suicide, as much as he had to have known he was playing with mortality.

The actor had a massage scheduled for that day, his "friend" Helena Christensen says she was on her way over to Heath's apartment when his body was found, and he was in the middle of filming a new movie. If for nothing else, there was the apple of his eye, Heath's 2-year old daughter Matilda, who friends called "his one joy."

As speculation swirls and controversial reports come in (the latest is that Heath struggled with heroin addiction), we can only wish his friends and family the best and remember him for the great actor he was.

*Update: NO ILLEGAL DRUGS WERE FOUND!!! A rolled-up $20 bill was found, but there was NO drug residue on it as earlier reported.