Pakistan has refused permission to a team of India's National Investigation Agency (NIA) to visit that country to interrogate the masterminds of the 26/11 Mumbai terror attacks and gather evidence against them.
The refusal comes at a time when India is considering a request from Pakistan to send a judicial commission here to interview key witnesses and other officials in connection with the trial of seven suspects in 26/11 Mumbai terror attacks case in Pakistan.
In a communique, Islamabad conveyed to New Delhi that the law of that country does not allow a probe by any foreign agency in any case there, sources said.
It conveyed that Pakistan's request to send a commission to India cannot be equated with the Indian plea as Islamabad has sent the request following a court proceeding.
Islamabad also told New Delhi that there was no Mutual Legal Assistance Treaty between the two countries and so the request cannot be accepted.
However, sources said, Pakistan's refusal to allow the NIA team to visit that country was another tactic to delay the probe into Mumbai terror attack case as New Delhi would like to send the team only after approval of the relevant court.
India is also suspicious about Pakistan's sincerity as it is yet to hand over the voice samples of the masterminds of the Mumbai attack, as promised earlier, citing a lower court order.
Sources said if Islamabad had the sincerity to bring the perpetrators of the crime to justice, it would have approached the concerned high court or the Supreme Court of Pakistan to challenge the lower court order.
Last month, Home Secretary Gopal K Pillai had said "no real investigation" has taken place in Pakistan and the prosecution's attempt in that country to bring the 26/11 guilty to justice "has not moved an inch" even as India's request for providing the voice samples of the handlers of the attackers has fallen on deaf ears.
When Home Minister P Chidambaram had asked for action against the 26/11 perpetrators and voice samples of handlers of the attackers during his Islamabad visit last year, his Pakistani counterpart Rehman Malik told him that "you would not be disappointed by our response".
Pillai had said "seven months down the line, there is no Pakistani response. We are disappointed."
No key person, who was actually involved in the 2008 Mumbai terror strikes or giving directions to the attackers, has been arrested in Pakistan. Only second or third-level conspirators were put behind the bars.
"That is not a real investigation," he had said.
On the eve of the second anniversary of the Mumbai terror attacks in November last year, India had conveyed to Pakistan that "substantive and verifiable" progress has not been made in the probe into Mumbai attacks case in that country.