A truly horrible, grisly multiple murder occurred on a quiet street near City College in March 2012, and it was called one of the worst mass slayings in SF's history. The main suspect in the case was Vietnamese immigrant Binh Thai Luc, now 38, and this week he appeared for his preliminary hearing in the murder of Vincent Lei and four of his family members, motivated apparently by money and gambling debts.

As the Chronicle reports, though it was originally reported right after the murders that a gambling debt may have been involved, it appears that that debt was not between Lei and Luc, but between Luc and someone else — and Luc appeared to have a very serious gambling problem that may have also led to his arrest in a 1998 armed robbery in San Jose.

Luc served eight years jail time for that crime, at which point he was going to be deported, but the Vietnamese government refused to take him back. At that point he was released from federal custody under a Supreme Court ruling that says undocumented immigrants must be released after six months if their country won't take them back.

The preliminary hearing on Tuesday, at which Luc was sent on to stand trial on all five counts of murder, revealed the basic outlines of the case against him, which are chilling

As was previously suspected, Luc apparently showed up at Lei's home where he lived with his parents, sister, and wife looking for Lei, with whom he'd played Mahjong. Prosecutors say he was there to rob the family of their cash in order to fuel his own gambling addiction, and that's where the motive ends — the defense will be arguing that there's no evidence of a debt between the two men, or any animosity.

Lei proceeded to leave a friend whom he was with to return home after getting a call from his wife that Luc was waiting for him. It appeared via the earliest reports in the case that Luc then murdered Lei's mother and father, sister, and wife, and laid in wait for Lei to return, at which he killed him as well. All the victims died of blunt-force trauma to the head, as well as knife wounds to wrists.

Luc then proceeded to try to muddy the crime scene and any blood evidence by dragging a hose into the house and dumping paint, bleach, and cooking oil over various blood stains.

Among the physical evidence against him: a fingerprint matching Luc's found on a Windex bottle at the home; and a pair of jeans found at Luc's apartment covered in 18 blood stains, with blood and skin cells matching at least three of the victims.

Luc stands accused of murdering Vincent Lei, 32; his wife, Chia Huei Chu, 30; his father, Hua Shun Lei, 65, who was a line cook at R&G Lounge; his mother, Wan Yi Wu, 62; and sister Ying Xue "Jess" Lei, 37, a software engineer.

A second sister, aged 40 at the time of the crime, was said to have been the one to discover the bodies. Neighbors at the time said she came screaming out of the house saying "they killed my brother" and "can someone please help me?"

Previously: Gambling Debt Cited As Possible Motive For Quintuple S.F. Murder