"We're not ruling out the fact that there may be a second or third suspect. We're looking at everything," he said.
Biel went inside the house for the first time Friday, along with the lead homicide inspectors and the assistant district attorney on the case, Linda Allen. The bodies were discovered at 16 Howth Street a week ago Friday.
Biel said he wanted to see the site himself so he could better visualize and understand when it's being discussed in meetings. Biel is in charge of investigations.
The street was blocked off for the eighth straight day, while investigators continued to process what is really four separate crime scenes inside the house. Sources say the killer threw bleach and paint all over the house to try to destroy evidence.
A large group of mourners brought flowers, lit incense and burned what appeared to be pretend cash in an urn outside the home. An older man sobbed as he struggled to light incense on the windy street, and another woman wept as she kneeled in front of the urn.
No one from the group of more than a dozen wanted to talk to reporters, but they did say they were co-workers of 62-year old Wan Yi Wu. They said she worked at the Serramonte Target store, and that she was a "great lady," a "good worker."
Five bodies -- a mother, father, adult daughter and son and his girlfriend -- were discovered last Friday morning. Police have not disclosed a motive, though sources say it had to do with gambling debts.
Thirty-five year-old Binh Thai Luc is in custody for the killings. He is scheduled to be arraigned late next week.