San Francisco police arrest Binh Thai Luc in connection with the "gruesome" killing of five people

(CBS/AP) SAN FRANCISCO - A San Francisco man was arrested Sunday on suspicion of killing five people, found dead in a home Friday morning.

Binh Thai Luc, 35, was taken into custody Sunday morning and booked on five counts of murder, police chief Greg Suhr said. The bodies of three women and two men were found Friday by a woman with access to the home.

The gruesome and tangled crime scene has investigators struggling to identify the victims and determining the cases of death.

Police initially thought they were dealing with a murder-suicide and were unsure if the suspect was at large. They also originally thought at least two of the victims were shot.

CBS San Francisco reports a man was found in the threshold of the home, while a man and woman were found in the garage. Another woman was found upstairs and a third woman was found downstairs, according to police.

"This was a complex crime scene. We had five deceased persons apparently from blunt force trauma. We didn't know what we had," Suhr said. The victims still have not been identified and police have not been able to offer a motive for the slayings.

The chief declined to say what led investigators to Luc, saying only that the suspect knew the victims and that an "edged weapon" was involved in the slayings. He said Luc had a prior criminal record, but did not elaborate.

Also arrested was Luc's 32-year-old brother, Brian Luc, on unrelated charges of drugs and ammunition possession and violation probation. Suhr did not provide details of the younger brother's arrest, saying only that the two lived together.