A 38-year-old tour operator from Vietnam was found dead along with a male victim in what police have called a double killing by an unknown assailant in a Las Vegas Strip hotel room, authorities said Monday.

Sang Boi Nghia died from multiple stab wounds, the Clark County coroner said.

Police said the attack probably happened about 2 a.m. Friday. At least one person later reported arguing had been heard in a room at Circus Circus hotel-casino.

The coroner did not immediately release the dead man's name, pending notification of his family.

Las Vegas police Lt. Ray Spencer told reporters Friday that both victims were stabbed multiple times.

He said authorities had not made an arrest but there was no active threat to guests at the nearly 3,800-room high-rise hotel. Spencer did not immediately respond Monday to telephone and email messages seeking further details.

Nghia's daughter, Chau Nghia, told the Las Vegas Review-Journal that her mother owned a tour business in Ho Chi Minh City, Vietnam. She identified the man who was killed as a tour employee. The Associated Press did not immediately find contact information for Chau Nghia.

Sang Nghia and the man were part of a Vietnamese tour group that arrived Thursday in Las Vegas from Los Angeles, police said.

Officials said police were summoned after hotel security went to the room at the request of tour members who became concerned that Sang Nghia and the man didn't show up for a trip to the Grand Canyon.

The Vietnam Embassy in Washington, D.C., did not immediately respond to emails about the case from AP.

Spencer said police would examine hotel security video to retrace the victims' steps and to identify any possible assailants.

A statement from Brian Ahern, spokesman for MGM Resorts International, said the hotel owner was cooperating with the police investigation.

The tour group left Las Vegas on Saturday for Los Angeles and the return trip to Vietnam, officials said.