Jessie attended the November 21 Meetup. During the meet up she was wearing a hamsa necklace similar to Jessa's, and it was revealed that she was Evan's ex-girlfriend, but that they remain good friends. She was Jewish as confirmed by the guys in a Ustream.
Jessie's grandmother Rose was murdered in a brutal way that seems to implicate The Rake. (See the video Rose. and detailed in the accompanying newspaper article.) The article also reveals that Jessie's grandfather is named William. It should be noted that Rose and William are also names that appear in the original Rake creepypasta, in the section referring to Linnie.
Jessie spent several weeks with her family, mourning her grandmother, but on March 21st Vince tweeted that she was due back that day, and that the crew was going to speak with her about Dr. Corenthal. The record of that event can be seen in The Corenthal Connection (Jessie's back), where Jessie confirmed that Corenthal was her mother's half-brother, and presents the boys with a binder of his materials found her grandmother's things. Included was the lease and keys to the storage locker that they visit later in that video.
In the video "Jim Thorpe" the boys arrive at Jessie's home in Pennsylvania to find her house open and The Rake inside. It was revealed in the next video (Jessie) that she was killed during the attack.