A state jury this morning found a homeless man guilty of manslaughter in the killing of a man in the parking lot of a Manoa church.

David Orpin, 60, had been charged with murder in the death of Arthur Martinez, 62, in October 2010 in the parking lot of St. Pius church.

Orpin faces a mandatory 20-year prison term at sentencing in October.

He had faced a mandatory minimum term of six years and eight months because the victim was at least 60 years old. But the jury found that Orpin did not know, or could not have known, Martinez’s age.

Orpin walked into Honolulu Police Department headquarters on Oct. 27, 2010 and told police he killed Martinez in the parking lot of St. Pius church in Manoa after Martinez harassed him.

Martinez was bludgeoned and died of head injuries.