sixth Idea...
There was an average Joe who worked at a glue factory manufacturing horses to glue. he was a production manager... but one night he took his mask off before entering a safe zone and smelt the glue. he got high instantly. he loved it so much he broke his mask and would get high everyday, this was his first and last mistake because eventually something in his head snapped and altered his thinking turning him crazy but he was one of those who had a collected spirit so he was cal in his madness.
he did hate where he worked so this became his M.O. to break free of the rules that held him to his job so in this mind state that he'd collected he ended up burning every barn within a 3 mile radius and slept peacefully.
The next day he woke up and this was all over the news... on his phone were a bevy of missed calls from his work place he called them up just to see what they wanted, they wondered why he was missing from work he still needed to go in as there were still horses to process and all the dead ones came to them, something about recycling. so there was major backstroke he ended up thinking what will happen when they finish with all these horses.
he came to the conclusion that there were still animals around... the local zoo has animals so in his warped mind state he thought of this as the obvious choice to hit next but this time he broke in rounded up all the animals got them into his truck and drove all the way to the coast and drowned them, dropping them from a cliff making sure that they wouldn't be found.
but there are obvious security cams in the zoo so they i.d. him got to his apartment and admitted it and told them all the animals were drowned in the ocean. they booked him and when it came to trial they declared him mentally unfit and put him in an asylum as "the pritt stick prick" that is what they call him.