In ‘The Perfect Storm’ (1x09) towards the end of the episode, Lucas comes up to Hanna in the school hallway and states that Hanna’s leather jacket has been sold. In the -A ending, -A is seen watching a video of Alison and is wearing a leather jacket. The only characters in the series who do actually wear leather jackets are Aria and Toby. But Aria has indicated that Toby isn’t -A, but it doesn’t mean he isn’t a helper. As the scene ends, the camera lingers over the envelope. The handwriting is pretty much identical to Aria’s.
In ‘Keep Your Friends Close’ (1x10) the girls are introduced to FBI Agents, Cooper and Randall. The video of Alison that the girls are watching was sent to the Rosewood Police Department (most likely Wilden). After Agent Cooper introduces herself and her partner, Agent Randall, a small smirk had come across Aria’s lips. Aria is also seen sporting a black leather jacket and black leather high heel boots. After Agent Cooper paused the video, she asked the girls what they could tell her about the video;
“They’re at the kissing rock. It’s in the woods behind the lake.” - Emily
‘I think this was taken the night that she died. She was wearing that yellow top.” - Aria
“But, that’s not her sweater. Ask what’s in our closets and I’ll give you an itemised list. I know clothes.” - Hanna
“I think she’s talking to the older boy.” - Spencer
About 21 minutes into the episode ‘Keep Your Friends Close’ (1x10), the girls are getting ready with their camping gear in the House of Hastings. After hearing that the blood stain on Toby’s sweater was confirmed as Alison’s blood. Aria says this;
“No, Alison wasn’t dating Toby. There’s no way that he’s the one in the video.” - Aria
How is Aria so certain? Well, maybe it’s because Aria knows Alison better than anyone else does. We know Pigtunia went missing the night Alison disappeared, so if Aria was following Alison around, then she would clearly know that neither Spencer, Toby, Ezra, Ian, Garrett or Byron killed her. It means that she had a motive to date Ezra, because she knew that he was writing a book about Alison and it probably had incriminating evidence against her.
About 28 minutes and 45 seconds into the episode “Keep Your Friends Close’ (1x10), Toby is seen rocking a black leather jacket. Leather is most commonly made from cow skin. The name Byron means ‘cowshed’ in Old English. Is Byron Toby’s father? Toby comes clean and is completely honest with Emily;
“Jenna told me that she’d tell people that I forced myself on her. She didn’t want it to stop.” - Toby
“Jenna wanted to be with you?” - Emily
“Jenna was in love with me. She’s still in love with me.” - Toby
“I asked Alison to meet me so I could tell her she did me a favor. She got me away from Jenna.” - Toby
“Why did you give her your sweater? And why did she meet you at the kissing rock?” - Emily
“We didn’t go anywhere. We met right outside of Spencer’s barn. I gave her my sweater because it was cold. When I left her she was getting in the car with some guy. Still wearing my sweater. She was very much alive.” - Toby
Aria knew that Toby wasn’t dating Alison because of the fact that Spencer told the girls that she kissed Ian and how Alison reacted to it. Aria was the only one who was able to put two and two together. But then this proves that Ella is also Jenna’s Mom, which explains why Aria and Jenna seem to get along so well. Jenna also seems to trust Aria more than the other liars.