Paul Gilstrap is a character featured in Season 4. He is a research scientist who was plotting to poisoning his own wife, by poisoning one of her Neptune bars with tetrachlorodrine. Knowing he couldn't count on the police to not name him as a murder suspect, he began going to a store poison other Neptune bars to make it look like a serial killing. After being caught at the lab with the tetrachlorodrine, Paul needed to destroy the evidence and restart but immediately saw an Armored Truck Guard, purchase a Neptune bar and partake in it. Outside the store, the guard immediately began to suffer from side effects and died on the scene, so Paul grabbed the Guards gun and shot him to make it look like he was shot rather than poisoned. He soon realized that another Neptune bar was purchased by Ambrose Monk to be given away on Halloween. He dressed up as Frankenstein's monster and began stealing candy from his trick-or-treaters to find the evidence. His plot was eventually discovered and he was arrested by Stottlemeyer and Disher.
It is unknown the reason why he wants to kill his wife.