Lucas has been a good friend to Hanna on “Pretty Little Liars” — but is he actually working for A.D.? That’s a new theory emerging after the return of Jenna Marshall in episode 4 of the Freeform series.

Aria (Lucy Hale), Emily (Shay Mitchell), Hanna (Ashley Benson) and Spencer (Troian Bellisario) were shocked to see their old high school nemesis walk through The Radley lobby. But Jenna (Tammin Sursok) didn’t appear surprised to hear them. And after a phone call to Dr. Elliott Rollins’ burner phone, it seems pretty safe to say that she’s been plotting with A.D.

Episode 4 concluded last week with Mona (Janel Parrish) and Hanna stumbling across Elliott’s secret phone thanks to a call.

“Hi, Archer,” the caller said when Mona picked up. “Can you hear me? It’s Jenna. Jenna Marshall.”

The phone call ties Jenna to Elliott and Mary Drake, who we know teamed up to get money from the Carissimi Group. It’s not clear how Jenna knows Elliott, or what they are working together on, but there may be another player involved.

When the Liars returned to Rosewood in Season 6, Lucas (Brendan Robinson) just so happened to run into Hanna. In the five-year time jump, Lucas became a successful game app developer, owning a couple of homes and indulging in other luxuries. He offered his studio apartment up to Hanna to stay in, and she’s been there ever since. It was a generous offer — and not his only one for Hanna. He essentially gifted Hanna with her own clothing line.

How can Lucas be considered a suspect after everything he’s done for Hanna? “Pretty Little Liars” fans can’t forget about one small detail from Season 6. In episode 9, the girls were banned from prom due to security issues. However, that didn’t stop their classmates from celebrating. Looking at photos online, they discovered that Lucas and Jenna were prom dates.

Are Lucas and Jenna still close? Do they ever talk? It’s certainly a possibility.

The promo video for episode 5 teases that Jenna will come face-to-face with Alison for the first time in years. Alison calls Jenna out for knowing about Archer, yelling that he can go to hell. Jenna replies that Archer may already be there.

Aria, Emily, Hanna, Spencer, Alison and Mona are the only people that were there the night Elliott/ Archer was killed. So, how would Jenna suspect that he’s dead? She could have somehow got the information from Lucas since Hanna was driving his car that night. Although Mona claims that she got the broken and bloody windshield fixed at a place that asks no questions and doesn’t talk, Lucas certainly has the money to make someone talk. He also could have put a tracking device on his car, or even a camera.

Could Lucas be a villain on “Pretty Little Liars”? Tweet your thoughts to @AmandaTVScoop.