MARBLEHEAD – In a cliff-hanger vote, selectmen have appointed Jason Conrad as the newest sergeant in the Marblehead Police Department. Conrad, the son of Police Sgt. Marion Conrad and the highest scorer on the Civil Service list, will begin his duties on the night shift Sunday.Police Chief Robert Picariello recommended Conrad to take the post vacated when Sgt. Brian Hitchcock retired.Thirty-year Patrolman Nicholas Economou said his communication skills were his most important asset and he recalled sitting with victims of property crimes as a way to build relationships between the police and the community. Ten-year Patrolman David Ostrovitz told the board, “Sometimes the best action is the one that is not taken.”Chief Picariello told selectmen he recommended Conrad on the basis of his Civil Service score but added, “I have full confidence in all the candidates.”Selectman William Woodfin said he always found it immensely difficult to make appointments and produced a stack of information he downloaded from the Internet indicating that Civil Service evaluations are imperfect at best.Selectmen Chairman Harry Christensen responded, “I?m not managing the department. That guy (the chief) is.”