ACCRA, Ghana — Authorities in Ghana say a Peace Corps volunteer who stabbed and killed an alleged robber in July will not be prosecuted and that all charges against him have been dropped.

Regional police commander Kofi Adei-Akyeampong said police dropped the case against Andrew Kistler, an American, following the attorney general's investigation.

"The AG has advised against prosecution, so we dropped the case," said Adei-Akyeampong.

Regional attorney general Robert Beke said, "I advised that [Kistler] acted in self-defense so the case should be dropped."

Police said Kistler used a knife in self-defense and stabbed an attacker in the chest in the northern town of Wa in July.

During the attack, Kistler, who was accompanied by a second Peace Corps volunteer, was injured with a machete. One of the two attackers, Eliasu Najat, 22, was found dead the morning after.