"Brainwashing helps in various ways" -Crona49
Crona49 is an alternate account that was made by Gabeharrison49 to cause chaos on the Wiki. While Crona49 existed, he was thought to be a totally different person because the behavior and patterns didn't match those of Gabe. He was thought to be a friend or a sibling.
During Crona's first appearance on the Wiki, he was friendly and very helpful to everyone. It would just be a little over a month until Crona49 was used for more sinister things. Things such as being used to cheat on others while in a relationship, major and very out place threats, and even at one point joining The Composer in his terror.
It wasn't found that Crona was Gabe until Gabe's "Departure". Especially when looking through his email and seeing all accounts were hooked on one email, which also happened to be his email for his main account.