LONDON — Hours before he was scheduled to be executed last month, the Pakistani hit man made an incendiary accusation.

Speaking into a video camera at a remote desert jail, Saulat Mirza, a death-row convict from the port city of Karachi, said his orders to kill had come from Altaf Hussain, the city’s most powerful and, until recently, untouchable political leader.

“Altaf Hussain directly gave us the murder instructions,” Mr. Mirza said in footage that was broadcast on several television news channels later that evening in March.

It was enough to earn Mr. Mirza a last-minute reprieve, as the authorities investigated his claims. Mr. Hussain, for his part, called it a conspiracy to damage his image.