JOINT BASE LEWIS-McCHORD, Wash. — Army prosecutors asked an investigative officer to recommend a death penalty court-martial for a staff sergeant accused of killing 16 Afghan villagers in a predawn rampage, saying Tuesday that Staff Sergeant Robert Bales committed ‘‘heinous and despicable crimes.’’

Prosecutors made their closing arguments after a week of testimony in the preliminary hearing. Prosecutors say Bales, 39, slipped away from his remote base at Camp Belambay in southern Afghanistan to attack two villages early on March 11. Among the dead were nine children.