JOHANNESBURG — Family and friends of a slain South African police commander who was involved in anti-corruption investigations have attended a memorial service in his honor.

The service for Maj. Gen. Tirhani Maswanganyi was held Monday in the Johannesburg area of Soweto.

The officer was found dead a week ago in a field near the South African capital, Pretoria, according to police. His hands and feet were bound.

Mzwandile Petros, the provincial police commissioner, says Maswanganyi was overseeing several sensitive cases including alleged corruption involving several police officers. The slain officer was also scheduled to testify in a murder trial.

Police say they are investigating possible motives for the killing.