What does Ali from pll know about Toby?

The night that jenna was blinded, Toby and Jenna were in there tree house. Toby used to do thing to Jenna, inappropriate things. The night Ali set of the firework, she was distracted by what she was seeing happeing in Jenna and Toby's tree house, she set it off and hit Jenna in the eyes, blinding her. But what is told in the 4th book is that Ali and Jenna planned set the firework of that night together, and Jenna told Ali she had family problems (meaning Toby) and wanted toby out off her life for good, and since Toby's parents and threatened to sen hi to boarding school if he set another firework of (which he was banned for because he did it to much) they knew Toby would be sent away. So Ali new what he did to jenna all those years, and Ali blackmailed Toby sailing that if he takes the blame for blinding Jenna, she wouldn't tell his parents what he had been doing to her. CONFUSING I KNOW! And also, since mona was the 1st A, she new how Jenna got blinded, not from ali's diary but because she was there hiding in the bushes watching, and she has scars on her stomach/chest from where the firework sparks caught her.

Hope this helps:-)