Islamabad: Research papers dealing with immunity for heads of states were the only things stolen from the home of a Supreme Court official, a media report said on Friday.

The apex court is hearing a contempt case against Prime Minister Yousuf Raza Gilani for not acting against President Asif Ali Zardari for corruption. Gilani has refused to act, citing immunity for Zardari as he is the president.

Senior judicial assistant Yousuf Jan Marwat was working, among several assignments, on the president's immunity as reported.

Thieves broke into his home when none of his family members were present. The only thing missing was the documents he was working on as a researcher for Chief Justice Iftikhar Mohammad Chaudhry, sources said.

Gilani had appeared before the Supreme Court Jan 19 in the contempt case for not acting against Zardari and defended his move, saying that the constitution provided immunity to the president.

The apex court had warned the government of action if its ruling on the National Reconciliation Ordinance (NRO), which granted immunity to politicians and bureaucrats in corruption cases, was not implemented by Jan 10, 2012.