Guards searched San Quentin State Prison for convicted killer Mark Adams, who failed to return from a job assignment. “We’re concentrating inside the walls,” prison spokesman Dave Langerman said. “If the passage of time indicates he has escaped, we will seek outside help.” Adams, 23, was sentenced to 43 years to life for first-degree murder in Stanislaus County. Langerman said that in either late 1981 or early 1982, Adams fired 17 shots from an assault rifle at two people who were uncooperative during a robbery attempt in a park. One was killed and the other severely wounded.