CARACAS, Venezuela (AP) — Nelson Martinez, the jailed former head of Venezuela's state-run oil giant PDVSA who was arrested last year as part of anti-corruption purge, died in state custody Wednesday, authorities said.

The chief prosecutor's office said Martinez suffered from a serious and chronic illness that led to his death at a medical facility where he was undergoing treatment.

The death is likely to focus attention on the conditions in which authorities are holding key opponents and former government officials. Martinez died two months after a Caracas councilman, Fernando Alban, fell to...