This week, Mel Gibson's legal team will depose the rogue bodyguard who claimed he and Oksana Grigorieva were intimate, and the actor's advisers are banking on him becoming a crucial witness in a bid to clear him criminally, RadarOnline.com has exclusively learned.

The interrogation of Kristian Otto Herzog, a twice-convicted felon who once impersonated a cop with a loaded firearm, has been set down for Friday, February 4.

The Lethal Weapon star's lawyers have subpoenaed documents and photos that Herzog has previously claimed detailed his relationship with the Russian musician, 40, in anticipation of the deposition.