Mick Jagger Tuesday said he is "still struggling to understand how my lover and best friend could end her life in this tragic way," as investigations try to piece together what motivated the apparent suicide of his longtime girlfriend, designer L'Wren Scott.

In a Facebook post that included Scott's photo, the rock icon thanked fans for their support and said he and the famed designer "spent many wonderful years together and had made a great life for ourselves."

Jagger, 70, is reportedly en route to New York City from Australia, where the Rolling Stones were scheduled to perform seven concerts, which were all postponed Tuesday in light of the tragedy.

An assistant found Scott, 49, whose real name is Luann Bambrough, unconscious and hanging from a doorknob by a scarf inside her apartment at 200 Eleventh Avenue on Monday morning. No suicide note was found and there were no drugs inside the apartment, according to the police.

The city's Medical Examiner scheduled an autopsy Tuesday to determine the cause of death. No timetable was given for the results.

Scott designed dresses for dozens of celebrities and dignitaries, including Michelle Obama, Jennifer Lopez and Penélope Cruz.

Scott and Jagger met in 2001 at a fashion show and were last photographed together at a gala in November. Jagger's representative yesterday slammed a story printed in another New York City newspaper that said the couple had recently broken up.

"There is absolutely no basis in fact to this story. It is a horrible and inaccurate piece of gossip during this very tragic time for Mick," the spokeswoman said in a statement.

Scott's fashion businesses, however, did appear to be going through some rocky times recently, according to financial records.

Her company, LS Fashion LTD, which is based in London, reported a negative net worth of $5.5 million in 2012.

Scott's family has asked for privacy since her death and no information on memorial services has been released.

Several celebrities including Marc Jacobs and Madonna expressed their condolences Monday, as did Bianca Jagger, Mick Jagger's first wife.

The Rolling Stones singer, who had dated Scott since 2001, said he was grateful for all of the thoughts and well wishes.

"I have been touched by the tributes that people have paid to her, and also the personal messages of support that I have received. I will never forget her," he said at the end of his post.