A white powdered substance containing heroin was found in the Uganda hotel room where former "The Amazing Race" producer Jeff Rice was found dead last week, officials said.
Police in Uganda are now waiting for Katheryne Fuller, who was in Kampala to help Rice film a documentary, to recover after she was found unconscious on a hotel balcony next to Rice last Friday. Both were rushed to a hospital where Rice was declared dead from what authorities believe to be a cocaine overdose.
Officials will question Fuller regarding the substance found in a plastic bag in their room and the South African woman could be charged with breaking drug laws after she tested positive for cocaine in her system.
A source told ABC News that Fuller was conscious, but was slurring her words and didn't know immediately where she was.
"The bag of white powder that was found on scene is a mixture of a component of heroin and some Tylenol and some caffeine," Dr. Stephen Cina, a forensic pathology consultant, said. "So that certainly suggests that at least in that bag there's a mixture of several substances present."
Fuller is still in a Ugandan hospital in critical condition. Police were awaiting permission from Interpol to release her to go back to South Africa, and also to release Rice's body to his family in South Africa.
"Ms. Fuller is slowly recovering, and when she is recovered enough we will be able to talk to her and find out more about what happened," Uganda Police Force spokesman Asuman Mugenyi said. "She is not able to speak. Although she is responding to the treatment, she is not yet available to explain what transpired."
Fuller's father is with her and hoping to take her home to South Africa for medical treatment, but Mugenyi indicated Fuller might not be allowed to go home soon.
Because she tested positive for cocaine, she likely broke Uganda's drug laws, Mugenyi said. According to Ugandan police, the two are believed to have voluntarily ingested the substance.
"There was no struggle. These were two people in their room and there was not a single sign of a struggle. Not even a single bruise on Rice's body," Mugenyi said.
Mugenyi dismissed earlier reports that Rice might have been poisoned after a run-in with local "thugs." Many friends find it hard to believe that both he and Fuller could have simply overdosed.
Sources said Rice, 39, and Fuller might have been working on an investigative documentary and fear they might have been targeted. But Uganda police say they were hired by the Minnesota-based Starkey Hearing Foundation to shoot a documentary about the work of a non-profit in Uganda that provides hearing aids to people who can't afford them.
"I was shocked," Josh Gates, a friend of Rice's said. "Jeff was someone who was terrific at his job. I don't know exactly what to think about what happened to Jeff. I hear conflicting reports coming out of the region."
Ugandan police said they have now ruled out food or drink poisoning.
"This is a very wrong account," Mugenyi said. "Very wrong."
Sources close to Fuller told ABC News her passport and wallet were missing from her hotel room, though it's unclear whether they were stolen or taken as a part of the police investigation. The missing items and identification are complicating the efforts to have her moved back to South Africa.
Rice was a veteran producer who worked on the latest season of the hit reality-TV series "The Amazing Race" and the Emmy-nominated Animal Planet series "Whale Wars." In addition to raising two young kids, Rice and his wife, Sally Blackman, operated a television and film production company called SB Productions in Durban, South Africa.
Rice's family is waiting for his body. His wife posted the following message on her Facebook page Thursday: "To my dear husband Jeff - tragically you left this world and only time will heal the void that you leave behind. Rest in peace my darling."