E. Lamb (alias)

Identity
It is unknown to the audience who exactly "E. Lamb." Is for sure. We do know that Toby Cavanaugh's face and the identity is printed on an ID card to get into Radley Sanitarium, and a parking pass that was discovered by Emily and Hanna. Toby may or may not be the true "E. Lamb". Viewers are led to assume that Toby has been using the fake ID and Parking pass to pose as someone that has connections with Radley.

Season 3
In "Misery Loves Company", Spencer finds the first attribute to "E. Lamb." In a drawer in Toby's Apartment. This is the clue that leads her to believe that Toby is on the A-Team and is helping Mona Vanderwaal. When Spencer finds Toby looking for the A key in her kitchen one night, Toby is busted and asks Spencer how long she knew he was on the A-Team. She shows him the ID card and smacks him across the face. Toby never tells Spencer anything about E. Lamb because he is forced to escape when Spencer's mom walks in.

In "Out of Sight, Out of Mind", Emily and Hanna are searching Toby's apartment for possible clues leading to where he has disappeared to. While flipping through the pages of a biker book Emily had given to Toby as a birthday present, They reach a page with a green and white parking pass in it. There's no secret that it's a parking pass for Radley Sanitarium. It has a number and letter code and once again, the name "E. Lamb" Is printed on it. The girls question who it is, but Emily remembers Spencer told her that Toby called himself E. Lamb to get in and out of Radley.