Craft said Harris was formally charged with murder and Head with obstruction of justice, a third-degree felony. An extradition hearing will be held in California.
Head is believed to have family in California, Craft said.
Additional charges against more people are possible.
A $5,000 reward was offered information leading to Harris’ arrest.
Harris is suspected in the shooting death of Shepard at about 12:30 a.m. at his Nelson Street residence.
Shepard died of his injuries after being flown to Miami Valley Hospital in Dayton.
The incident happened when an intruder entered an upper floor apartment and shot Shepard during a reported exchange of gunfire.