After two long weeks with no fresh episodes, "Pretty Little Liars" season 6 returns with another explosive installment that could challenge the Liars' beliefs about Charles. 

In one of the sneak peeks for episode 6 titled "No Stones Unturned," Charles seems to be making his dad feel his presence when a birthday card is seen clipped to Mr. DiLaurentis' (Jim Abele) windshield wiper. Ali and Jason's dad appears to be pretty shaken when he sees that the card came from his supposedly dead eldest son, but it is Emily (Shay Mitchell) who receives his fury.

Em is just biking around the area and happens to pass by the DiLaurentis property when the fuming mad Mr. DiLaurentis begins yelling at her and angrily asks her who put the card in front of his car. 

The card's contents, however, is not disclosed in the teaser clip. 

Meanwhile, Sara (Dre Davis) begins working for Caleb's (Tyler Blackburn) "company" as part of her emancipation request process to get away from her messy home situation. In another sneak peek, she asks Caleb more information about Alison. Apparently, Charles also asked her to wear the same yellow sleeveless blouse and jeans worn by Ali when she disappeared, just like what he ordered Mona to do when he abducted her. 

Sara wants to know more about the girl who she was portraying at the Dollhouse for a long time. Caleb asks her why she did not mention it to Emily. Sara says that she already did but Em just shuts down whenever she asks questions about her old friend. 

The official synopsis for "Pretty Little Liars" season 6 episode 6 reads:

With all signs pointing to Lesli as the tormentor in the hoodie, the PLLs are on a mission to get concrete proof before bringing their findings to the police. But as the girls ramp up their investigation, 'A's' threats escalate. ​Meanwhile, a friend of Emily's makes her a surprising offer, and Spencer is pressured by her family to make an important decision."

The Liars will also realize in the upcoming episode that Charles implanted a tracking device on each of them.

"Pretty Little Liars" season 6 episode 6 airs on Tuesday, July 14, on ABC Family.