Mary-Kate Olsen is set to be questioned by police about Heath Ledger's death. The 'Weeds' star - who was romantically linked to the 'Brokeback Mountain' star following his split from Michelle Williams last September - was contacted by Ledger's masseuse Diana Wolozin when she found the actor's body in his New York apartment. Olsen then sent her security staff to the apartment.

It has now been revealed that Wolozin called Olsen four times before calling emergency services, not twice as was originally reported. The additional calls were discovered when police examined phone records, according to National Enquirer magazine.

Wolozin discovered Ledger, 28, lying face-down and naked on his bed, surrounded by six types of prescription medication at 2.45pm on Tuesday. It is unclear why she called Olsen but she used the speed dial on Ledger's cell phone to contact her.

The Oscar-nominated actor and the former child star first became friends in summer 2006. Following his split from Williams - with whom he has a two-year-old daughter Matilda - in September last year, Ledger was linked to a string of women including Helena Christensen, Lindsay Lohan and supermodel Gemma Ward.

An insider claims he and Olsen dated on-and-off for the last three months. The source said: "Mary-Kate and Heath were casually dating. They were hooking up, but neither were particularly interested in making it exclusive."

"They had a bond that was based on partying, and they had the same tastes in partying 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."

Olsen has an apartment in New York with her twin sister but was in California at the time of Ledger's death.