KAMPALA, Uganda -- An American television producer found dead on a hotel balcony in Uganda last week died after taking contaminated cocaine, police and a private investigator said on Saturday.

An official toxicology report confirmed the narcotic was in Jeff Rice's blood, dispelling initial suspicions the father of two known for his work on the U.S. show "The Amazing Race" had been poisoned by attackers.

Rice, who was found slumped over a table bleeding through the nose and mouth, died of asphyxiation, a post mortem showed. Drug users who fall unconscious risk inhaling vomit.

"Rice ... used cocaine which had lethal additives and that's what killed him," Uganda police spokesperson Asuman Mugenyi told Reuters.

Brad Nathanson, a private investigator and friend of Rice, said he had been shown the toxicology report by police and there was no evidence of foul play in Rice's death.

"In fact it was as a result of buying bad drugs, cocaine to be specific ... it was a bad concoction," Nathanson told reporters.

"I have read the toxicology report ... it shows that there were small traces of cocaine in their blood and urine," he said, adding he had traveled to Uganda as a friend of the Rice family following rumors he had been poisoned, and not for payment.

Rice's assistant, identified as Kathryne Fuller, was found unconscious when Rice's body was discovered Feb. 18 at the Serena hotel in the capital, Kampala. She is now reported to be conscious but paralyzed down the right side of her body.

Early on, there had been speculation that the two had been poisoned, then that they might have been forced to consume the drugs, because of the high amount of cocaine in Rice's stomach. NBC News contributor Clint van Zandt said on the "TODAY Show" on Saturday that it seemed unlikely that Rice would have willingly taken that amount of cocaine. 

If Rice and Fuller were believed to have voluntarily consumed the drugs, Fuller could be prosecuted under Uganda's drug laws.

Ugandan police said on Saturday they had arrested a man who confessed selling drugs to the pair who had been in the east African country working on a documentary.

Fuller's father said he was "disappointed, sad" but would support his daughter, a South African.

"We all do stupid things in life. Unfortunately this is a large mistake but we can't exactly crucify her," Stewart Fuller said.

Fuller's family hopes to move her to South Africa for treatment.

Msnbc.com staff contributed to this report from Reuters.

More from msnbc.com and NBC News:

• Canadian sled dog killings prompt new rules
• 'Occupy Toilets': Chinese women seek extra seats
• Gunman kills 2 US Army officers in Afghan Interior Ministry
• South Africa's Mandela admitted to hospital

Uganda police are keen to interrogate a South African woman who was found unconscious in a hotel room along with the body of American television producer Jeff Rice, NBC News reported.

Kathryn Fuller, a production assistant, was found last week in the same room with Rice, a freelance producer for the American reality TV show “Amazing Race.” She was taken to The Surgery, a hospital in Kampala.

"We sent a team of detectives there today (Friday) but found that she was still too weak and so could not interrogate her. The team may return tomorrow," Deputy Kampala police spokesperson Ibin Ssenkumbi said.

Police on Wednesday said forensic tests indicated that Rice died of a cocaine overdose and that Fuller had also taken the drug. 

Police were still grappling with a request by Fuller's relatives to have her transferred to South Africa for more advance medical treatment, according to NBC News. The relatives pledged to bring her back to Uganda once she improves.

"We have not yet recorded a statement from her and are waiting for her to improve. Additionally, her travel documents are still missing and that complicates matters," Ssenkumbi said.

Kathryn's father, Stewart Fuller, flew to Uganda and has asked police to allow him transfer her to South Africa. But police said they were finding the request a difficult one, given the circumstances.

Senior Uganda police officers, including the national police chief, Lt. Gen Kale Kayihura, on Thursday checked on Fuller at the medical facility.

A decision on her transfer would depend on doctors' assessment of her condition, police said.

'Amazing Race' producer Jeff Rice found dead in Uganda

Fuller and Rice, police said, checked into the Kampala Serena Hotel last Friday, having moved from the Lake Victoria Serena Resort. On Saturday morning, Rice was found dead on a sofa on the balcony of their hotel room while Fuller was unconscious on the floor.

The two had flown into the country on Feb. 15 to work on a documentary, according to ABC News.

Ugandan police say it appears the two voluntarily ingested the drug.

"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," police spokesman Asuman Mugenyi told ABC.

More from msnbc.com and NBC News:

• Rebels plead for weapons to make vision of post-Assad Syria happen
• Dutch riled at Santorum's euthanasia comments
• 12 die as Afghan Quran-burning protests resume despite Obama's apology
• Australia's 'dingo baby' mystery finally solved?
• Beijing's pollution could cut 5 years off lifespan, expert says

An American television producer has been found dead in mysterious circumstances while working in Uganda, his brother-in-law told msnbc.com on Wednesday.

Paul Blackman said that family members had heard that poisoning was suspected in the death of father of two Jeff Rice, 39, who is originally from Oklahoma.

Blackman, who is the brother of Rice's wife Sally, added that the situation was unclear and relatives were trying to establish what exactly had happened

Rice, who previously worked for shows including "The Amazing Race" and Animal Planet's "Whale Wars," died on Friday night. 

Rice's assistant, who Blackman declined to name, also became ill and was taken to a hospital in Uganda.

"We've sent people up there to get some answers," Blackman told msnbc.com by phone from Durban, South Africa. "Nothing is finalized yet.

Addressing media reports that Rice had been fatally poisoned, Blackman said: "I don't know where they are getting this 'definitely poisoned' thing."

Rice moved to South Africa about 13 years ago and holds dual citizenship, Blackman said. His wife is South African.

Rice's death was first reported by FoxNews.com.

'Really tough to handle'
Blackman said Wednesday morning that he was looking after their children, girls aged seven and two, while Sally Blackman tried to get information from the South African police.

He said his sister was finding the uncertainty "really tough to handle, but, yeah, she's strong."

"There's so much stuff in the air about possible poisoning, all that kind of stuff," Blackman said. "At the moment, we're trying to get Jeff's body out of there to get some answers."

Blackman said Rice had been "a historian, tour guide kind of person" in the United States and had started to work in television about three years ago. He and his wife ran SB Productions in Durban.

He added his brother-in-law was working on either a future show or documentary in Uganda.

"He was a fantastic producer apparently, a very, very sought-after producer," he said. "The messages (of condolence) coming in have been very, very good actually. It's been fantastic, he's a very well-liked character. He was a good guy, very relaxed and just a very good guy."

The "about us" section of SB Productions' website says Rice decided there were "better ways to spend his time" after five years "contributing to the stalemate of the 405 in LA."

"From pie in the sky to looking no futher than his nose, his mind is always churning. If Jeff isn't crunching budgets or breaking down scripts, he can probably be found in some unusual African location with his Power Book and a bottle of the local brew. Jeff has an incredibly calm nature and a wicked sense of humor," it adds.

More from msnbc.com and NBC News:

• Former 'Amazing Race' producer found dead in Uganda
• Palestinians cheer pending release of hunger striker
• Wildlife officials fear 'epidemic' in rhino poaching
• Journalist beatings erase optimism in China