WASHINGTON (AP) — The defense team in the Blackwater trial attacked the testimony of a key prosecution witness Thursday, telling a jury that the witness lied to federal investigators even after he had sworn to tell the truth in an effort to win leniency in the case surrounding the killings of 14 Iraqis.

The witness, former Blackwater guard Jeremy Ridgeway, undercut the defense of four of his former colleagues. The four say they acted in self-defense, firing their weapons because they believed they were under attack by insurgents.