Thai police escorted the U.S. schoolteacher to Bangkok airport for deportation, Fox News reported.
He is scheduled to arrive in Los Angeles at 8:40 p.m. PDT.
After a day or two he was then expected to be flown to Boulder, Colo., for questioning after telling reporters in Bangkok that he was with the 6-year-old beauty queen when she died in 1996, but her death was an accident. The little girl was found in the basement of her family home the day after Christmas.
Karr faces charges of first-degree murder, kidnapping and child sexual assault.
New information about Karr includes his seeking treatment at a Bangkok clinic specializing in sex-change operations.
"Yes, he had treatment here," a representative of the Pratunam Clinic, Thailand's top transgender center, told the New York Daily News.
But the representative would not say how close he was to getting "sexual-reassignment" surgery.