Chicago Trial May Unmask Pakistan’s Links to Militants

Mr. Headley told Indian investigators that the officer, known only as Major Iqbal, “listened to my entire plan to attack India.” Another officer with the intelligence service, the Inter-Services Intelligence Directorate, “assured me of the financial help,” Mr. Headley said.

As the United States presses Pakistan for answers about whether the ISI played a role in harboring Osama bin Laden, Mr. Headley is set to recount his story of the Mumbai attack in a federal courthouse in Chicago. What he discloses could deepen suspicions that Pakistani spies are connected to terrorists and could potentially worsen relations between Washington and Islamabad.

India, the site of the November 2008 attacks, will be monitoring the trial for evidence of the ISI’s duplicity. Pakistan will also be listening to — and is likely to deny — Mr. Headley’s every word. Islamabad has been dismissing his accusations against the ISI as little more than a desperate performance by a man hoping to avoid the death penalty.

An American official who spoke on the condition of anonymity said that the United States government’s view of Mr. Headley — like the debate that has raged in Washington about the ISI for the last decade — was bitterly divided. No agreement exists in Washington on whether the ISI guided Mr. Headley and the attacks on Mumbai.

“It’s not very clear,” the official said. “A lot of this is going to come out of the trial. His claim could just be his claim.”

Still, the very fact that the government is presenting Mr. Headley as a prosecution witness suggests that at least some in the government believe he is telling the truth. And the authorities said they expected the government to present e-mails and tapes of telephone conversations to support his story.

Any new evidence of ISI malfeasance that emerges from the trial will reverberate in Washington, with the relationship between the United States and Pakistan at its most tenuous in years.

A growing chorus on Capitol Hill argues that the discovery of Bin Laden’s hideout and the evidence in Mr. Headley’s case leave no doubt that the ISI and its Pakistani military overseers have played a cynical double game with the United States. Pakistan has received $20 billion in military and development assistance since 2001, and its military, they say, has sheltered Bin Laden, supported Afghan Taliban who kill American troops and guided the militants who attacked Mumbai.

Mr. Headley himself is not on trial. But he will be the main witness against Tahawwur Hussain Rana, a Chicago businessman who is accused of providing financial and logistical support for the 2008 siege in Mumbai. The attack, a barrage of gunfire and grenades, killed at least 163 people, including six Americans. Mr. Rana’s defense is that he agreed to support Mr. Headley’s activities in India because he was led to believe he was working for the ISI, and therefore the Pakistani government.

Bruce O. Riedel, a terrorism expert at the Brookings Institution and former Central Intelligence Agency officer, predicted that the trial would be “the next nail in the coffin of U.S.-Pakistan relations, as the ISI’s role in the murder of six Americans is revealed in graphic detail.”

American authorities have kept much of the evidence secret. Citing national security concerns, they have successfully moved to quash the defense lawyers’ subpoenas for State Department cables and records held by the F.B.I. that discuss Pakistan’s links with militants.

And though the government has charged four other men, including the officer known as Major Iqbal, with aiding and abetting the murder of American citizens, the indictment refers to them either as commanders or associates of the militant group Lashkar-e-Taiba, not as having links to the ISI.

In interviews in recent days, American military and intelligence officials who have served in Pakistan argued that the ISI’s story is complex. Some of them portray it as an unwieldy bureaucracy that even Pakistani generals struggle to control. The United States should try to reform the ISI, they argue, not abandon it.