After a passerby found a three-year-old girl with blood on her feet wandering alone in a Louisiana parking lot, authorities embarked on a multiday search for her missing mother: Lyntell Washington, a Baton Rouge educator who was voted Teacher of the Year. When authorities found the pregnant teacher shot in the head, they were left with a cryptic clue from her toddler, who said: “Mr. Robbie” hurt her mother. A new episode of “20/20” unpacks the shocking crime, including how the investigation led authorities to identify one of the assistant principals at her school, Dr. Robert Marks, as the killer.

Contributing anchor Deborah Roberts reports the two-hour program, which features exclusive interviews with Washington’s close friend and former supervisor, Jamicia Pink-Fisher, and two jurors who served on the murder trial. It also includes never-before-seen recordings of police interviews with the suspect, the 3-year-old who was an eyewitness, and exclusive security camera footage. “20/20” also has interviews with Leslie Parms, who first found Washington’s young daughter abandoned in the parking lot; District Attorney Tony Clayton; Iberville Parish Sheriff Brett Stassi; and Washington’s best friend, Melissa Mason. “20/20” airs on Friday, Oct. 7 (9:01-11:00 p.m. EDT) on ABC, streaming next day on Hulu.

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