If convicted of treason, Musharraf could face the death penalty or life in prison. But the federal government would have to file charges against the former military ruler, which it has not yet done. The petitions in Islamabad High Court accusing Musharraf of treason were all filed by individuals.
Musharraf faces similar accusations from petitions filed before the Supreme Court. He also faces legal charges in two other cases. One involves allegations that Musharraf didn't provide adequate security to former Prime Minister Benazir Bhutto, who was killed in a gun and suicide attack in 2007. The other relates to the death of a nationalist leader in Baluchistan in 2006.
Given the legal challenges and Taliban threats against Musharraf, many experts have been left scratching their heads as to why he returned. Some have speculated he misjudged the level of public backing he would get, while others guessed he was simply homesick.
Musharraf flew to the southern city of Karachi from Dubai on March 24. He was only met by a couple thousand people at the airport, a sign of how little support analysts say he enjoys in the country. A few days later, an angry lawyer threw a shoe at Musharraf as he was walking through a court building in Karachi.
The former military ruler applied to run for parliament from four different districts in Pakistan, which is allowed by the country's political system. Judges initially rejected three of his applications, but an official in the remote, northern district of Chitral gave him approval to run.
That changed Tuesday when the High Court in the northwestern city of Peshawar disqualified Musharraf in Chitral. He can appeal the decision to the Supreme Court, but legal experts speculated that chances the decision would be overturned were remote.
Dozens of police and elite commandos blocked the main road leading to the compound where Musharraf was holed up on the outskirts of Islamabad on Thursday and residents were asked to use another route to go to their homes.
About 20 Musharraf supporters who gathered near the compound held banners and shouted slogans in favor of the former military ruler.
Associated Press writers Rebecca Santana and Munir Ahmed contributed to this report.