Home secretary GK Pillai says Pakistan's efforts to prosecute those behind the 2008 Mumbai attacks are a "facade" with Islamabad concerned that senior government officials might be implicated.
In an interview published in the Wall Street Journal on Monday, GK Pillai said India had provided Pakistan with extensive information on the identities of key conspirators behind the attacks that killed 166 people.
Some of the most compelling evidence was garnered from interrogating David Headley, a Pakistani-American who pleaded guilty to surveying the hotels and other targets ahead of the assault blamed on Pakistan-based militants.
Pillai said Headley had identified the voice of key conspirators from Indian intelligence intercepts and the information had been passed on to the Pakistani authorities.
"I don't think they're going to do anything about it," Pillai told the Journal, adding that Pakistan's moves to advance the case are a "facade" and ignored the people in the "control room" who orchestrated the attacks.
Pillai argued that Pakistan was wary of cracking down on top militants, for fear they will "sing" and implicate Pakistani government officials in the attacks.
"They just can't do it," he said.
The Mumbai attacks, which began on November 26, 2008, caused carnage as 10 heavily-armed terrorists stormed Mumbai, sparking a bloody, 60-hour siege shown live on television around the world.
Nine of the terrorists were killed and the sole survivor, Mohammed Ajmal Kasab, was condemned to death by a Mumbai court in May. He is challenging the sentence.
Seven suspects in Pakistan, including alleged mastermind Zakiur Rehman Lakhvi, have been put on trial in the country, but none has been convicted.
The trial process has stalled, with Pakistani officials demanding Kasab be allowed to testify, which New Delhi has refused. Pakistan also wants to send a fact-finding commission to India to gather more evidence.
India sees these moves as stalling tactics and says it has handed over enough evidence to convict the accused men. Pakistan says the evidence is inadmissible in court.
The Mumbai attacks continue to dog relations between India and Pakistan, whose slow-moving peace process broke down after the assault.