Did Grandma Order a Hit? "20/20" Investigates Grandmother Accused of Masterminding Son-in-law’s Death

ABC's 20/20 returns for a new year and asks an interesting question – did a 75-year-old grandmother put a hit out on her own former son-in-law?

What's Happening:

• Dan Markel was a prominent Florida State University law professor. But in 2014, he was found gunned down in his Tallahassee home. As authorities begin investigating his murder, they identify someone close to home as the possible mastermind behind the killing: Donna Adelson, Dan’s former mother-in-law.
• Dan was embroiled in a bitter divorce and custody battle with Donna’s daughter, Wendi, and prosecutors say this 75-year-old grandmother orchestrated an elaborate murder scheme. 
• Correspondent Ryan Smith brings viewers inside a case that 20/20 has been following for a decade – bringing you all the twists and turns of this case, including the latest on the trial, verdict and murder that shattered a family and shocked the nation.
• 20/20: Meddler or Murderer? airs Friday, January 2nd (9:00-11:00 p.m. EDT) on ABC, and streams the next day on Hulu and Disney+.

More Disney TV News:

• Get ready for one of the biggest TV reunion events of 2026 with a new teaser from Hulu for the limited series Malcolm in the Middle: Life’s Still Unfair.
• Hulu is gearing up for the release of A Thousand Blows Season 2 with a special look at the upcoming season with writer and executive producer Steven Knight. 
• ABC will welcome in 2026 with live coverage of the 137th Rose Parade from Pasadena, California on New Year's Day.
• While Season 2 of Percy Jackson and the Olympians just hit Disney+, we have new casting announcements for several anticipated characters coming to the series’ third season.