DATELINE: Unthinkable: The Menendez Murders

Tonight, “Dateline NBC” will air a special two-hour episode on the Menendez brothers, who were convicted more than two decades ago of murdering their parents in Beverly Hills.

During an interview with NBC’s Keith Morrison, the older brother, Lyle Menendez, argues from behind bars that despite admitting to the brutal shotgun killing of his parents, he believes he should have received a plea deal. Lyle tells him, “There are, like, two to three hundred parricide cases a year, where a parent is killed by a child. And they are almost all related to abuse. And they are almost all settled. This case, they picked out as different.” He added, “And I think that it was very easy, because it was Beverly Hills, and my father had a lot of money, to sort of sell this headline that these brothers killed for money.”

Friday’s broadcast features a comprehensive look at the Menendez case, including an interview with former detective Les Zoeller, a rarely seen letter from Lyle to Erik, and an interview Erik did shortly after the murders.

Zoeller, who worked on the case, tells Morrison of an incident when Lyle and Erik showed up at their house hours after the murder, looking for their tennis equipment: “He [Lyle] said, ‘We want to get our tennis equipment.’ And I said, ‘Well, where is that?’ He said, ‘It’s in the library where my parents were murdered.’” Zoeller added, “he was matter of fact and didn’t seem very upset to me.”

“Unthinkable: The Menendez Murders” also includes interviews with key players, such as: Lyle and Erik’s cousin Diane Hernandez, former prosecutor Pamela Bozanich, tennis coach Bill Kurtain, former neighbor Alicia Hercz, Dr. William Vicary, jury members Hazel Thornton and Andrew Wolfberg and criminal defense lawyer Cliff Gardner.