But on April 8, investigators, wondering how the assailant could have emerged from the woods without fearing he would be seen carrying a rifle, searched the site of the shooting once more and unearthed a rifle buried one foot below ground 200 feet behind the Slepian home. Clark, the Erie district attorney, said afterwards that investigators think the doctor's killer buried the rifle in the days before the shooting, unearthed the weapon to (fire) the fatal shots, then hurriedly reburied it and fled.  
 Verb: fire
Yes