thomas moriarty, seen here during a recent operation, performed surgery on the gun shot wounds to erica's head. these were cat scans of her skull and brain, preop. >> part of the bullets and broken bone. >> the mission was to clean the fragments from erica's head, repair the wounds and preserve brain function, if possible. erica was lucky in one way. the angle of the bullet wasn't straight through the brain, but downward, exiting under her chin. >> what a blessing as opposed to the bullet damaging everything. >> and dr. moriarty was relieved that the bullet only struck the brain's frontal lobe. >> less than 3 years old, the brain's ability the repair is truly remarkable. >> after the delicate three and a half hour surgery, dr. moriarty was encouraged by comparison scans of erica's brain. the bullet and the bone fragment in the preop image were gone. but despite the repair, brian injuries are unpredictable and dr. moriarty urged caution. >> the next few days will be critical. >> at the crime seen, detective arnold continued to sift through clues. more leads came into focus. a bloody footpr