The man who killed Chris Kyle may have done so after being influenced by an episode of Seinfeld, according to prosecutors in the trial of Eddie Ray Routh.

According to a psychologist who has spoken with Routh since the murder, Routh believed that “American Sniper,” Chris Kyle, and Kyle’s friend Chad Littlefield, were “pig assassins” who were out to kill him.

The idea of a pig assassin can be traced to a 1993 episode of “Seinfeld,” in which Cosmo Kramer talks of an evil entity known as the “pig man.”

Though Routh spoke of a similar evil pig, prosecutors don’t think that this corroborates his insanity.

According to authorities, Routh watched many hours of Seinfeld in prison after being arrested for the murder, and may have been influenced by the episode to try to fool law enforcement.