Frontline: Raising Adam Lanza 10 p.m., Channel 2

Many questions came out of the horrific shooting in Newtown, Conn., in December. This episode of “Frontline” finds the producers of PBS’s gold standard investigative series teaming up with the Hartford Courant to examine some of them, including an investigation into Adam Lanza’s background and the gun debate in Connecticut both before and after the tragedy,

Body of Proof 10 p.m., Channel 5

We have enjoyed actor Mark Valley in just about every, often short-lived, show he’s been in, from the most recent “Human Target” to “Boston Legal” to the great “Keen Eddie.” (Although to some of us he will always be our favorite Jack Devereaux from “Days of Our Lives.”) Valley arrives to the third season premiere of this procedural as Detective Tommy Sullivan, trying to relight the fire with medical examiner Megan Hunt (Dana Delaney). It’s not the first rodeo for Delaney and Valley. The pair appeared together in the, yup, short-lived “Pasadena.”

Go On 9 p.m., Channel 7

Terrell Owens takes a T.O. from football and goes to work for Ryan.

The Mindy Project 9:30 p.m., Channel 25

Medford meets Cambridge as Maria Menounos guest stars.

Smash 10 p.m., Channel 7

Daniel Sunjata to the rescue.