It seemed like everyone loved Mo. Which is why investigators were having a hard time figuring out who didn't… and why? Watch the full story tonight at 9/8c on a classic Dateline mystery with Keith Morrison. | Dateline NBC

“It was horrible. Worst thing I've ever seen.” The full story, tonight on an all-new 2-hour Dateline mystery at 9/8c on NBC. | Dateline NBC

The sun was barely up when the girl called 911… The full story tonight on a classic Dateline Weekend Mystery at 9/8c. | Dateline NBC

“It was horrible. Worst thing I've ever seen.” The full story, tonight on an all-new 2-hour Dateline mystery at 9/8c on NBC. | Dateline NBC

It was a nightmare in the farmhouse… Watch tonight at 9/8c on an all-new 2-hour Dateline with Andrea Canning. | Dateline NBC

“She called, screaming that someone was in their house.” The story tonight at 9/8c on an all-new Dateline. | Dateline NBC

Aya rushed back upstairs to that open window. And she looked down… Watch tonight at 9/8c on a classic Dateline Weekend Mystery. | Dateline NBC

It was the crime that ended Aya's childhood. But what happened that morning? Find out tonight on a classic Dateline Weekend Mystery at 9/8c on NBC. | Dateline NBC

She heard screaming. She didn’t realize it was coming from her… Keith Morrison has the story tonight on a classic Dateline Weekend Mystery at 9/8c. | Dateline NBC