Updated

The discovery of four bodies outside a Los Angeles home quickly led to the arrests of four people some 300 miles away and a day later in Las Vegas, police said.

The four suspects were being held at Clark County Detention Center awaiting extradition to Los Angeles, Las Vegas police said in a statement Tuesday. One was arrested for investigation of murder and the three others were for crimes stemming from the killings.

They were arrested Monday at the Silverton Hotel and Casino by Las Vegas officers after a request from Los Angeles police and the FBI. Las Vegas police learned that the suspects were driving a black Audi with no license plates, located the car at the hotel, and watched the suspects through the night until arrest warrants were issued.

Ka Pasasouk, 31, the alleged gunman, was arrested for investigation of murder, while three others were accused of being accessories to murder, committing robbery, or both, Los Angeles Police Chief Charlie Beck said at a news conference.

Pasaouk has a lengthy criminal record that includes convictions for robbery, assault and possession of methamphetamine, according to court records obtained by the Los Angeles Times. He was on probation at the time of the killings.

Police said the victims, whose identities have not been released, were visiting friends at an overcrowded, unlicensed boarding house in Northridge when they were confronted and fatally shot early Sunday.

"This is one of the worst and heinous crimes we've seen in our community," said City Councilman Mitchell Englander, who represents the area. "This is a community that once again will come together and never forget what happened at this location."

Englander 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. Englander called the living conditions deplorable.

Detectives were met with a "very grisly tableau" when they found the victims on a front lawn, Beck said. Three of the bodies were found face-down.

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

Glendale resident Howard Alcantara, 30, has been booked for investigation 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 or provide details about a motive, the suspects or victims, saying the investigation remained active.

Those killed were two women in their mid-20s, a man in his mid-30s and another man in his late 40s, police said.