Owen Chapman was a victim of a Visitor sleeper cell.
Erica Evans and Dale Maddox were investigating a sleeper cell, whose activity actually spiked after the Visitors' arrival. Erica also noticed that the same cell was acquiring large amounts of C4. Three weeks later, a truck suspected of having drugs was checked by the NYPD. They did not find drugs but did find, however, traces of C4. Erica and Dale went to Long Island where the truck came from and searched for C4. They did not find it in the silos but when they searched a shack nearby, they found a secret passage underground. They did not find the sleeper cell, but Erica did discover a dead body tied to a chair, large amounts of C4, and fake documents, passports, and IDs, some of which belong to Jeffrey Leclair. Erica identified the victim as Owen Chapman and found a search warrant for his house. The FBI went to his house, but it was cleared out again - as if the sleeper cell knew the FBI were coming. Erica found Owen's cell phone with a text message directing him to a meeting tonight about a sleeper cell. ("Pilot")