Investigators say the incident happened last month when 36-year-old Grishuk had a business meeting with him in Dana Point about starting a clothing and vitamin line.
She began to feel woozy, found a dissolving pill in her drink and called 911. Authorities originally said the pill was GHB, but toxicology tests determined the pills were actually Nimetazepam, a drug similar to GHB but one usually found only in Asia and Europe and not the United States.
Grishuk, who won gold medals for Russia in ice dancing in 1994 and 1998, had known Halstead for two years and felt "very comfortable with him," said Orange County Sheriff's spokesman Jim Amormino. He added that the two were not romantically involved.
The Associated Press contributed to this story.