Chances are, the three sleeping men never saw the knives that slashed their throats.

They were in a Toys R Us parking lot when they were attacked early yesterday, Prince George's County police said. Two died at the scene, and one was severely wounded.

The assault occurred about 6:50 a.m. in Langley Park, in a spot known as a gathering place for men to drink beer and often sleep. An unofficial pickup site for day laborers is half a block away.

The victims probably consumed alcohol and passed out on the grassy median of the parking lot in the 8100 block of New Hampshire Avenue, said a detective who declined to give his name because the case is under investigation.

"This was a vicious attack," said Cpl. Diane Richardson, a police spokeswoman. "We are very, very concerned about this."

Police say the killings remain a mystery; they have no suspects or motives.

"Not three months ago, I was here hanging out with them," said Daniel Fuentes, 38, who lives in Hyattsville and came by the scene, which was crowded for hours with startled onlookers. "It could have been me."

Fuentes said that some of the men who hung out in the parking lot were homeless and that others simply enjoyed the company and conversation in Spanish, their native language.

One slaying victim was identified as Cesar Mayorga, 34, who lived in an apartment in the same block as the toy store. Relatives said Mayorga, who was from Guatemala, would sometimes sleep outdoors. He was found shirtless.

The other man killed, Anibal Escobar, 28, of the 1300 block of Merrimac Drive in Langley Park, was discovered on a wide piece of cardboard that was doubling as a makeshift bed, police said. Neighbors said he was a native of Honduras.

Police did not release the name of the surviving victim, who probably will be a witness in the case.

Yesterday's incident, which took place close to the Montgomery County line, does not appear to be gang-related or connected to the stabbing of six teenagers last week in Montgomery, police said.

The slayings capped a violent nine-hour stretch in Prince George's that included a near-fatal stabbing less than a half-mile away and an unrelated homicide in another part of the county. Police are trying to figure out whether the knife attacks are connected.

Detectives recovered a knife from the homicide scene.

The slayings of Mayorga and Escobar are the 105th and 106th homicides in the county this year. Last year at this time, 84 people had been slain in Prince George's.

Toys R Us, which opened late yesterday, did not respond to e-mail requests seeking comment or return several phone calls.

Mayorga's cousin Geraldo Vasquez sat on a curb near his relative's body for hours yesterday morning. He said Mayorga had a job in construction and routinely sent money to his wife and three children in Guatemala.

Vasquez said his cousin would gather with about 10 men from various Latin American countries each night and drink beer in the spot where he was killed.

"I can't explain why he came out here," Vasquez said. "I never drank out here with him. But he never told me about any problems out here."

Fuentes, who said he met Mayorga several years ago, knew him only by his nickname, "Chapin," which is slang for man from Guatemala. He said he rushed to Langley Park when he saw news of the slaying on television.

"I came by to see if it was anyone I know," Fuentes said. "I am very surprised this happened. We never have violence like this here."

He said that about two years ago, he was in need of a meal and a place to stay, and Mayorga helped him out. "On the street, we made friends," Fuentes said. "He was a very nice guy."

Fuentes said police sometimes would come by the parking lot to see what people were doing there, but officers did not make them disperse. Fuentes said the men were careful to clean up their mess and sometimes picked up trash in the entire parking lot to keep it clean.

Police are offering up to a $25,000 reward for information that leads to an arrest and indictment in the case. Anyone with information is asked to call the Prince George's homicide unit at 301-772-4925.

Authorities investigate the scene of the Langley Park crime, which a police spokeswoman called "a vicious attack."