Legendary DJ Casey Kasem’s vicious family feud now includes allegations of murder and elder abuse — and is the focus of Saturday’s “48 Hours.”

The ongoing battle pits Jeannie Kasem — Kasem’s second wife — against his three children (Kerri, Julie and Michael) from his first marriage. It’s all laid bare by correspondent Peter Van Sant in Saturday’s episode.

“I have never seen such hatred within a family,” says Van Sant. “Both sides tell credible, powerful stories, both proclaim their love for Casey and both blame the other and accuse the other of killing Casey — and both use the word ‘murder.’”

Kasem died in June 2014 (on Father’s Day) at the age of 82 from a Parkinson’s-like disease — leaving behind an estate valued between $80-$100 million that he amassed by founding (and voicing) the internationally broadcast “American Top 40” radio show and its various iterations. He also notably played scraggly teenager Shaggy Rogers on the Saturday-morning 1970s cartoon series “Scooby-Doo Where Are You!” (Shaggy was known for his catchphrase “Zoinks!”)

Jeannie claims Kasem’s three grown children conspired in 2007 to trick Casey into signing over power of attorney, giving them control over his medical decisions (which ultimately killed him).

“It was always about the money,” she tells Van Sant. They, in turn, filed a wrongful death lawsuit against Jeannie claiming elder abuse when she moved Casey from a rehab facility in Santa Monica, Calif., to a friend’s home in Washington state. “Jean killed my father,” Kerri Kasem tells Van Sant … “The only thing she ever wanted from my dad is money.”

Jeannie countersued the children for forcing Casey to return to a hospital in Gig Harbor, Wash., where he eventually died. “Jeannie claims that once they had control of [Casey] and his medical decisions, they told his doctors to unhook his nutrition, hydration and medicine and left him to die,” says Van Sant. “She claims they wanted their share of his life insurance policy.”

Van Sant will also break the news on Saturday’s “48 Hours” that police in Gig Harbor have opened an investigation into Casey’s death, after a private eye hired by Jeannie concluded he was a homicide victim.

In a further twist, Kasem’s body rests in an unmarked grave in Oslo, Norway. “After he died his body was flown to Montreal and kept on ice there for a few weeks, then it was flown to Oslo,” says Van Sant. “As you’ll see … there’s a Swedish woman named Anki who visits his grave once a month and decorates it.” Van Sant says Jeannie won’t say why the grave is unmarked, but that Casey always expressed interest in Norway — though he’d never been there.

“The kids say it was done completely out of spite so they can’t visit the grave,” he says. “Both sides swear they will take this to court and fight it out — and both claim they will prevail.”