Asphalt John: Careful Who You Screw With

When fatherless boy Raul is attacked by a gang, he hires John, a homeless man, to protect him because Raul thinks he's a missing heroic FBI agent. John makes a clean spot in Raul's life, and soon must widen it, saving his mother from a predatory cop, and eventually facing off against the mob bent on revenge. They all think he's the FBI agent, but maybe John is someone far, far more dangerous.