Sam Haskell IV, the Hollywood scion accused of chopping up his wife and in-laws before tossing a disembodied torso into a dumpster, has died in a Los Angeles jail while awaiting trial, according to authorities.

Los Angeles District Attorney Nathan Hochman revealed in a statement that prosecutors had damning new evidence against him that was going to be made public at an upcoming preliminary hearing — including that he was having an affair with a 27-year-old woman and had been arrested with a bloodsoaked knife containing the DNA of all three victims.

Corrections officers found the 37-year-old dead in his cell Saturday, days before the hearing, where prosecutors were expected to outline the case against him. He previously pleaded not guilty.

Hochman’s office released a summary of the evidence prosecutors planned to unseal at the hearing.

After killing and dismembering all three victims, he allegedly paid $500 to a group of day laborers he asked to remove a series of heavy black trash bags from the home, where they all lived together, according to prosecutors. After picking up the bags, one of the workers looked inside and saw human remains. The day laborers gave the money and the bags back to Haskell and called police.

Sam Haskell on a trip abroad in August 2013.  (Sam Haskell/Instagram)

Investigators previously said that by the time officers arrived at his house, Haskell and the bags were gone. Fox News Digital also reported that surveillance cameras at a gym in Encino showed him placing a heavy bag in the dumpster outside. A homeless man looking through the trash made the gruesome discovery and called 911.

Police found his wife’s car, which had her stepfather’s blood inside, Hochman’s office revealed Monday. They tracked Haskell to an Airbnb nearby, which investigators allege he had rented for himself and the children he shared with Mei Haskell after the murders.

A general view of the home in Tarzana, Friday, Nov. 10, 2023, where Sam Haskell Jr. lived with his wife, Mei Haskell, and her parents Yanxiang Wang and Gaoshen Li. (Fox News Digital)

When police arrested Haskell, he was carrying a pocket knife and a Home Depot receipt from a few days earlier listing plywood, a moisture barrier, coveralls and diamond saw blades, Hochman’s office said Monday.

In his rented SUV, he had a loaded .357 revolver, 32 rounds, a blood-covered knife, the family’s passports and a one-way ticket to Japan, according to authorities. They separately seized $67,000 cash during a search on his office.

DNA testing on the knife matched blood to all three victims, according to prosecutors.

“You do have to take into account the timing of all of this,” Ritter told Fox News Digital. “He’s been in prison for some time. I imagine he had opportunities for this kind of action before now. But it does seem interesting that it would come on the eve of a date that would expose all of the horrible things that he’d been up to.”

A general view of the dumpster area off of Ventura Boulvard in Encino California, Friday, Nov.10, 2023, where Sam Haskell Jr. is alleged to have dumped his wife, Mei Haskell’s torso. (Fox News Digital)

Police later recovered eight more bags containing bloody evidence, but not the remains of his in-laws — and they said that “large amounts of blood” had been cleaned up at the family home.

As for Haskell’s alleged 27-year-old mistress, authorities say she told them Haskell told her in October 2023, shortly before the murders, that his parents would be taking over care for his children. Then he invited her on a trip to Japan. In addition to the one-way ticket he had, prosecutors say he bought her a round-trip ticket.

Sam Haskell appears in court for a preliminary hearing at the Clara Shortridge Foltz Criminal Justice Center in Los Angeles, California on Friday, Feb.16, 2024. Haskell took his own life before facing trial on three counts of murder in the deaths of wife Mei Haskell and parents Goashan Li and Yanxiang Wang. (Splash News for Fox News Digital)

“It’s interesting to me that, here’s a guy looking at life in prison without parole, multiple murders, it’s as bad as it’s going to get,” Ritter said. “There’s a strong likelihood that he will never see the outside of the prison again, but he is such a narcissist that he is more concerned with the embarrassment of perhaps his extramarital affair becoming exposed than he is with life in prison — if that is what motivated this.”

The remains of Mei Haskell’s parents have not been found.

Haskell’s parents, Hollywood producer Sam Haskell III and beauty queen and actress Mary Donnelly Haskell, are known for a series of Christmas movies. His father was also a former talent agent who represented George Clooney and Dolly Parton, among other A-list stars. He declined to comment.