Police searched for a third suspect today in connection with the shooting deaths of 13 people at a private gambling club in Seattle's Chinatown.

The suspect, a young Asian man, was believed by police to have been with the two young Asian men, both in custody, when the killings took place at the Wah Mee Club early Saturday morning.

Twelve of the victims were found "hog-tied" in the club's gambling room, and scattered around four felt-topped tables. The 13th was found unbound near the entrance to the club. Early autopsies showed the 12 men and one woman died of one or more gunshot wounds to the head.

Meanwhile, the lone survivor of the shootings, Wai Chinn, 62, who provided information that led to the two arrests, remained in serious but stable condition at a local hospital under heavy police guard.

Chinn, who was shot in the throat, managed to wriggle free from his bonds and stagger out into the alley, where he was seen by a passerby who called police.

All of the victims were connected with the restaurant business. Police said robbery apparently was the motive for the killings, one of the nation's worst single-day mass murders.

One source said between $1,000 and $10,000 is known to move nightly through the private, tightly guarded Chinese club. Only Asians known by club management are allowed inside, and police believe the victims knew their killers.

The entrance to the Wah Mee Club is an inconspicuous door next to an exotic pet shop, midway down a wide alley. Wah Mee means "beautiful China" in Chinese.

Little is known about the two suspects in jail, Benjamin K. Ng, 20, and Kwan (Willie) Mak, 22, except they were both born in Hong Kong and have been in the Seattle area a number of years.

Ng was in bed when police arrived to arrest him. Mak turned himself in Saturday. At least four guns, including two handguns, were seized at Mak's residence, police said.

Deputy King County Prosecutor Mary Kay Barbeiri said bail will be set Monday afternoon as high as $1 million.

Ng was arrested by Seattle police in January, 1981, in connection with shootings in which four Chinese men were hospitalized, one with serious injuries, according to juvenile court records. The assault charge was dismissed for insufficient evidence, records show.

Lt. Robert Holter, head of the homicide squad, said Seattle police were investigating whether there was any connection between the club killings and the July 16 slaying of two Asians.