Four suspects have been arrested in Las Vegas in connection with the slaying of four people who were found in the yard of an overcrowded, unlicensed boarding house in Los Angeles, police said Tuesday.

The arrests were made at the Silverton Hotel in Las Vegas.

Ka Pasasouk, 31, was taken into custody on suspicion of murder, while three others were accused of being accessories to murder, committing robbery, or both, Los Angeles Police Chief Charlie Beck said in a news conference.

Beck said detectives were met with a "very grisly tableau" when they found two men and two women fatally shot on a front lawn Sunday after police received a 911 call that led them to a large house in Northridge. Three of the bodies were found face-down.

The suspects will be extradited to Los Angeles in the next several days, Beck said.

Glendale resident Howard Alcantara, 30, has been booked on suspicion of robbery and aiding a felon. Donna Rabulan, 30, of Los Angeles was arrested for investigation of aiding a felon, and Christina Neal, 31, of Los Angeles was taken into custody for investigation of aiding a felon.

Beck declined to take questions at the conclusion of the news conference, or provide further details about a motive, the suspects or victims, saying the investigation remains active.

City Councilman Mitchell Englander, who represents the area, toured the house and said it was split into units for rent, including makeshift living spaces in the backyard.

He said it appeared to be operating as an unlicensed boarding house with at least a dozen and as many as 17 people living amid old food, trash, mattresses and animal waste.

"What lies behind those doors are deplorable living conditions that you wouldn't expect animals to live in," Englander told KPCC radio.

Police questioned several people who were on the property at the time of the shooting, and believe at least some of the victims lived at the residence and may have been related.

The people killed were two women in their mid-20s, a man in his mid-30s and another man in his late 40s, Capt. William Hayes said.

"There were two on the sidewalk path," Englander told KPCC. "The first victim was crouched over and the second was a little beyond that."