Two Americans found dead in a Hong Kong luxury hotel might have ingested the date rape drug Rohypnol, a newspaper reported Sunday, citing police.

The men — whom police identified by single names only, Paul and Richard aged 45 and 51 — were found dead in a room at the Grand Hyatt hotel on Friday afternoon.

The Sunday Morning Post, citing unnamed police sources, said the two men were found with white froth coming from their mouth.

The report said the case may have been an attempted robbery that went wrong involving the use of "date rape" drug flunitrazepam — a sedative sold as Rohypnol.

Police refused to confirm whether the two men were seen returning to the hotel with two women, saying "all options" were being considered, the paper reported.

Hong Kong police declined to confirm the report Sunday, saying more toxicology tests were needed.

"A post-mortem examination failed to find out the cause of their deaths, so more toxicology tests are being carried out," said a police spokeswoman who requested her name not be used due to policy.

The case was still classified as a "dead body found," she added.

In recent years, there has been a rash of cases reported to police in which men who went out in Hong Kong's lively nightlife district Wan Chai woke up the next morning apparently robbed — and with no recollection of what happened.

Rohypnol, commonly known as a date-rape drug, has sedative and hypnotic effects. People attacked, robbed or raped while under its influence can regain their senses with no memory of the assault.

Dale Kreschler, press officer for the U.S. Consulate in Hong Kong, said he could not comment on the case due to privacy concerns.