By Mubashir Zaidi
BBC News, Islamabad
A Pakistani court has asked the country's government and military intelligence to explain the disappearance of a nuclear engineer.
Attiqur Rehman played a key role in Pakistani nuclear technology
The father of Attiqur Rehman says that his son went missing two years ago.
He says that Attiqur was abducted on his wedding day by the country's intelligence agency (ISI).
Mr Rehman said that he had not seen his son since, despite ISI assurances that he would be released. But the agency says it does not know where he is.
Attiqur Rehman was a senior scientific officer working at the Pakistan Atomic Energy Commission. But two years ago, he went missing.
Mr Rehman was known to have worked with AQ Khan
His father, Sideburn Rehman, filed a petition in the Lahore High Court last month asking it to establish his son's whereabouts.
The court issued notices to the ISI chief and interior secretary last month to file a reply.
On Friday, the ISI issued a one-line statement telling the court that Attiqur Rehman was not in the ISI's custody, and that the agency did not know where he was.
However, Mr Rehman's lawyer has urged the court to seek a more detailed reply from the ISI.
The High Court judge, Justice Abdul Shakoor Piracha, said that government and intelligence agencies should respect civil liberties and take the case seriously.
The court ordered the ISI and interior secretary to file detailed replies on 13 June.
The disappearance could be related to the nuclear black-market
Mr Rehman's lawyer, Ikram Choudhary, later told the BBC that ISI personnel have privately been telling the family of the scientist that he would be home soon and the family should make arrangements for his marriage - which was meant to happen two years ago.
It is not clear whether Attiqur Rehman's disappearance is linked to Pakistan's nuclear black-market network headed by AQ Khan.
More than 11 senior officials close to Dr Khan have been interrogated on the orders of the government in the past two years. All of them were later released.
Pakistan's Foreign Office last month announced that investigations into the nuclear black-market network were over.
However, Mr Rehman's lawyer said his client's disappearance occurred at the same time as Dr Khan's aides were detained, which led his family to believe that he might have been questioned over the matter as well.