Joshua Lynch

was the UNSUB in the post-Season-One-hiatus extra Arlington. He was a junior high school teacher who molested and killed at least one of his students, Monica Fiore.

He was not a gamma; Peter Pauley was the BAU agent who wrote up the report on him (rather than one of the Shadow Unit team members). However, Chaz Villette helped the BAU on that case, and had nightmares about mirroring Lynch.