MEMPHIS, Tenn. (AP) -- Lawyers for a former corrections officer charged with killing two West Tennessee postal workers say his videotaped confession was illegally obtained because he was coerced by investigators and his requests to have a lawyer present during questioning were ignored.

Federal prosecutors argue that Chastain Montgomery's confession should stand because he was properly advised of his constitutional rights and he voluntarily spoke with authorities.

Chief District Judge Jon McCalla on Wednesday will begin hearing arguments related to Montgomery's statement that he and his 18-year-old son fatally shot Paula Robinson and Judy Spray during an October 2010 robbery of the Henning post office that netted just $63.

The younger Montgomery died in a shootout with police in Mason on Feb. 14, 2011. The elder Montgomery could face the death penalty at trial.