A gunman shot a Bronx mother in the back of the head in an execution-style killing as she brought her children to school this morning. The perp shot Lakisha Scriven, 30, at around 7:15 am while she helped her girls, aged 5 and 8, get into the car. Cops haven't determined a motive for the slaying, but a source told the Daily News "at this point" it looks like a hit. WPIX has a rather graphic aerial photograph of the crime scene. Neighbor Alicia Parks, 25, said the shooting woke her up: "I heard crying and screaming...The only thing I kept hearing was, 'Mommy!'...When I finally woke up I heard, 'The bad man killed mommy.'" The children — who were unharmed — did not recognize the gunman, according to the Daily News.