Thieves stole a laptop and a briefcase from the highly guarded residence of India's ambassador to Pakistan last month, a report on Monday said.
India said in November that it had lodged an official complaint with Islamabad over the incident, but did not provide any further details at the time.
A leading daily reported on Monday that two items had been taken from the house. The paper said it was "unclear what the laptop contained."
Although India earlier called the incident a "break-in," a Press Trust of India agency report has said that the burglary was now believed to have been done by an insider.
The theft occurred less than 10 days after Pakistani President Pervez Musharraf imposed a state of emergency on the country.
The two nuclear-armed South Asian rivals launched peace talks three years ago in a bid to improve ties.