He generally stayed out of his wife's first administration, but he and his associates became entangled in corruption cases linked to the government. He was largely blamed for the collapse of the Bhutto administration. After the dismissal of Bhutto's government in August 1990, Benazir Bhutto and Zardari were prohibited from leaving the country by security forces under the direction of the Pakistan Army. During the interim government between August and October, caretaker Prime Minister Ghulam Mustafa Jatoi, a Bhutto rival, initiated investigations of corruption by the Bhutto administration. Jatoi accused Zardari of using his wife's political position to charge a ten percent commission for obtaining permission to set up any project or to receive loans. He was tagged with the nickname "Mr. Ten Percent". He was arrested on 10 October 1990 on charges relating to kidnapping and extortion. The charges alleged an extortion scheme that involved tying a supposed bomb to a British businessman's leg. The Bhutto family considered the indictment politically motivated and fabricated. In the October 1990 elections, he was elected to the National Assembly while in jail. Bhutto and the PPP staged a walkout from the inaugural session of the National Assembly to protest Zardari's incarceration. He posted $20,000 bail, but his release was blocked by a government ordinance that removed a court's power to release suspects being tried in the terrorist court, which fast-track trials for alleged terrorists. The ordinance was later revoked and a special court acquitted him of bank fraud and conspiracy to murder political opponents. He was freed in February 1993. In March 1994, Zardari was acquitted of bank fraud charges. All other corruption charges relating to Bhutto's first term were dropped or thrown out of the courts. On March 25, 1991, the hijackers aboard Singapore Airlines Flight 117 demanded Zardari's release among other demands. The hijackers were killed by Singapore Commandos.

Answer this question "Wonder how long was he in prison?" by extracting the answer from the text above.
He was freed in February 1993. In March 1994, Zardari was acquitted of bank fraud charges.