Five years after his arrest, Binh Thai Luc, the prime suspect in a quintuple murder that's been called one of the worst mass slayings in San Francisco's history, finally stands trial. On Tuesday, prosecutor Eric Fleming of the District Attorney's office and Luc's defense lawyer, Mark Goldrosen, exchanged opening remarks before a jury.

According to the Chronicle's report of the proceedings, Fleming outlined the prosecution's case, and argued that Luc "is connected to this crime in many ways, from the beginning, middle and end." Goldrosen countered that though Luc may have been present at the time of the killings, he "had no reason, no motive to kill."

In the five years since Luc was arrested, the story about the motive for the murder has changed a few times, with investigators settling on a possible gambling debt owed by Luc. In a preliminary hearing from 2015, prosecutors outlined their case against him, describing in chilling detail how he visited Lei's Ingleside home to look for him but only found Lei's father, mother, wife, and sister, who also lived in that house. When Lei learned Luc was looking for him, Lei headed home only to find Luc lying in wait to kill him after he had allegedly already murdered Lei's entire family. The prosecution believes that Luc was motivated to murder Lei and his family because he also intended to steal money from them to pay off his gambling debt.

The SF Weekly reports that in today's hearing, Fleming also highlighted Luc's attempts at concealing his presence at the crime scene. He said, "He tried to hide evidence. He tried to conceal evidence. He tried to hide himself." At the preliminary hearing, the prosecution described how Luc allegedly tried to use things like cooking oils and paints to cover up and foul evidence, going so far as to try to run a hose into the house to flood it with water. Despite that, investigators found physical evidence linking Luc to the scene, including a fingerprint on a Windex bottle found at the home and a pair of jeans in Luc's home that had 18 different bloodstains, with a few of those stains matching those of Lei and his mother.

The crux of the defense's argument lies in emphasizing Luc's friendship with Lei, attacking the prosecution's alleged motive, and that the evidence found by investigators is all circumstantial. Goldrosen even went a little further, arguing that investigators didn't follow up any other leads after they arrested Luc and that police failed to look into a lead from an FBI informant who allegedly said that a Chinatown gang head had ordered the killings. In fact, it's worth pointing out that the hearing was delayed in 2013 because of the "sheer amount of evidence to sift through," according to defense attorneys.

All previous coverage of the Howth Street murders on SFist.