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 / Updated By Andy Eckardt and Cassandra Vinograd 
 
 MAINZ, Germany - An American nanny whose half-naked body was found in her Vienna apartment died of "suffocation," police in Austria said Thursday. 
 
 Lauren Mann, 25, was found at her home in the city Tuesday night. 
 
 Police are still treating the case as homicide "because third party involvement cannot be excluded," a spokesman told NBC News. 
 
 A "considerable" amount of blood was found at the scene though an initial autopsy failed to determine cause of death. 
 
 A final autopsy showed that she died of "suffocation," police said Thursday, adding that the case has been handed to the Vienna prosecutor's office. 
 
 A spokesperson for the prosecutor's office would only say that the "investigation is ongoing and we will need to wait for results." 
 
 American authorities are assisting in the investigation, according to the U.S. State Department. 
 
 Toxicology testing has been ordered, though final results "could take up to a couple of weeks," police spokesman Thomas Keiblinger told NBC News. 
 
 He said "no specific suspect" was being investigated, adding that police have been speaking to Mann's neighbors and friends. 
 
 She had been living in Vienna for several years, working as an au pair while studying. 
 
 She grew up in the small Colorado town of Paonia and graduated from the University Of Colorado-Boulder in 2012, according to NBC station KKCO. 
 
 Paonia resident Lisa Heinritz said Mann had taken dance lessons with her daughter as a child. 
 
 "She always seemed like a really happy little girl and had a lot of friends," Heinritz told KKCO. ||||| VIENNA -- Austrian police told CBS News on Thursday that a 25-year old Colorado woman whose half-naked body was found in her Vienna apartment was not strangled, shot or stabbed, but they could not yet rule out homicide. 
 
 The autopsy, which allowed investigators to rule out those three potential methods of attack, was nonetheless "inconclusive,"officials said. 
 
 Vienna police spokesman Thomas Keiblinger told CBS News the results of a toxicology report were not expected for at least a week, possibly two, and the cause of her death was still under investigation. 
 
 Keiblinger said Wednesday the woman's body was found after she did not show up at the home where she worked as an au pair and her employer called police. 
 
 The U.S. government has identified her as Lauren Mann. 
 
 Speaking Wednesday on Austrian television, Keiblinger said "so far, this case must be treated as a murder because a third-party responsibility can't be excluded." 
 
 Police and firefighters who forced open her door Tuesday evening found the half-naked body on a mattress in the bedroom. 
 
 Mann graduated in 2012 from the University of Colorado-Boulder's College of Music. Spokesman Ryan Huff says the university was saddened by news of her death. ||||| Police have concluded that a Colorado woman who was found dead in Vienna this week had died from suffocation. 
 
 Lauren Mann, 25, had been living in the Austrian capital and was working as an au pair, or nanny, for a local family. She was found dead in a pool of blood on Tuesday at 6 p.m. in her apartment, according to Vienna police. Her body was half-undressed, according to Thomas Keiblinger, a Vienna police spokesperson. 
 
 Today, the city's prosecutor Nina Bussek told ABC News that Mann had suffocated. Investigators have not yet determined if someone else was involved in her death. 
 
 Keiblinger previously told ABC News that a preliminary autopsy showed Mann has not been stabbed or strangled and there were no external wounds on her body. 
 
 There are no suspects or arrests at this time, according to police. Officers have been in contact with Mann's friends. 
 
 Lauren Mann/Facebook 
 
 The family for whom Mann worked said in an interview that Mann was "very reliable, trusted, caring and socially active." Family members became concerned when one of their children was not picked up from school on Monday. 
 
 Mann's neighbor Peter Kratochwill told ABC News it was "extraordinary" for something like this to happen in "a neighborhood that is so quiet and safe." 
 
 The U.S. Embassy in Vienna is providing consular assistance. 
 
 ABC News' Louise Dewast contributed to this report. ||||| An American nanny has been found dead in the Austrian capital, police said Wednesday. 
 
 Vienna Police spokesman Thomas Keiblinger said the 25-year-old was found partially dressed in her apartment on Tuesday night after her employer got worried when she failed to turn up. 
 
 Lauren Mann Facebook profile photo. via Facebook 
 
 "We are still awaiting the final autopsy report, but are presently treating this as a homicide case," Keiblinger told NBC News. He did not go into further detail on possible cause of death, but said the victim was discovered next to a "considerable amount of blood." 
 
 Police did not fully identify the victim, describing her only as Lauren M., originally from Colorado and working as an au pair while studying in Austria. 
 
 Both the U.S. Embassy in Vienna and the U.S. State Department confirmed the death of an American named Lauren Mann. Those officials said the embassy was assisting Austrian authorities on their investigation. 
 
 "We extend our deepest condolences to her loved ones," the embassy and State Department said in a statement.
– Officials have released a name in the case of the American nanny found dead in her Vienna, Austria, apartment on Tuesday night, but beyond that, much remains unclear. ABC News reports Lauren Mann, 25, died by suffocation, though it notes that Vienna police rep Thomas Keiblinger earlier referenced a preliminary autopsy that found no indications of strangulation. NBC News echoes the report of suffocation, but CBS News and the AP report the autopsy was inconclusive, and their reports don't mention suffocation. CBS cites officials who on Thursday confirmed Mann was not strangled, shot, or stabbed. The case is being treated as a homicide, and an official tells NBC News "third party involvement cannot be excluded"; police say there are no suspects at this time. Keiblinger says it'll take a week or two for the toxicology report to be completed, which has CBS saying her death "could be [a] mystery for weeks." ABC reports Mann failed to pick up one of her charges from school on Monday, but her half-dressed body wasn't found until 6pm the following day. The Colorado native was a graduate of the University of Colorado-Boulder's College of Music.