Pakistan's Intelligence agency ISI had links with Mumbai attack co-accused Tahawwur Hussain Rana and David Headley, the prosecution submitted during the trial of Rana that opened in the US on Monday.

During opening statements at Chicago's Dirksen Federal Building, Assistant US Attorney Sarah Streicker said that Rana, a Pakistani-Canadian, told Headley, an American of Pakistani origin, after the Mumbai carnage in which 166 persons were killed in November 2008 that the ‘Indians deserved it.’

Streicker said Rana provided cover for his longtime friend Headley who took photos and videos of targets in Mumbai before the attacks and that Rana led Headley to pose as a representative for his Chicago-based immigration businesses.

The trial of Rana is being closely watched worldwide for what testimony might reveal about suspected links between the Pakistan-based terror group Lashkar-e-Tayyaba(LeT) blamed in the attacks and the country's powerful intelligence agency ISI, which has been under scrutiny after Osama bin Laden was killed by US forces on May 2 outside Islamabad.

Rana (50) has pleaded not guilty but Headley (50) his old friend from military school in Pakistan pleaded guilty. The arguments in the trial are being heard by a 12-member jury.

Charlie Swift, Rana's lawyer, said Headley was Rana's good friend and the Pakistani-Canadian was duped by him.

Rana did not know that his business was used for cover, Swift said, adding Headley had a bad boy's image in college.

"The defendant didn't carry a gun or throw a grenade. In a complicated and sophisticated plot, not every player carries a weapon. People like the defendant who provide support are just as critical to the success," Streicker said.

Rana's attorneys say their client was simply duped by his longtime friend and didn't know what was in store.

Headley and Rana, who has lived in Chicago for years, met at one of Pakistan's most prestigious military boarding schools and stayed in touch as adults.

Swift told jurors that Headley was a ‘manipulative man’ who ‘balanced multiple lives’ including working for Laskhar-e-Tayyaba(LeT), Pakistani intelligence and the US drug enforcement administration at the same time.

But Steicker said Rana knew what he was getting into. She said Rana provided cover for Headley and led him to pose as a representative for his Chicago-based immigration business.

"The defendant knew all too well that when Headley travels to a foreign country, people may die," Streicker said. Streicker said the government will show jurors evidence including emails between Headley and Rana that were written in code. She said Headley considered Rana ‘his best friend in the world.’

Rana is the seventh name on the indictment, and the only defendant in custody. Among the six others charged in absentia is ‘Major Iqbal’ and Sajid Mir, allegedly another LeT supervisor who also ‘handled’ Headley.

Headley, an operative of LeT, a co-accused in the Mumbai trial case may spill the beans about his links with ISI during the trial, media reports said. The trial of Rana could reveal ISI's links to terrorists and any evidence of spy agency's ‘malfeasance’ would worsen US-Pakistan relations, the ‘New York Times’ reported recently. Headley, who himself is not on trial will be the main witness against Rana, is set to recount his story of the Mumbai attack during the trial, it said.

Headley, 50, Rana's old friend from military school in Pakistan, claims that two years before terrorists struck Mumbai, he began laying the groundwork for the attack, financed by $25,000 from an officer in Pakistan's powerful intelligence service.

Headley had 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 ISI Directorate, "assured me of the financial help,’ the Times said.

Pakistan has been dismissing Headley's accusations against the ISI as little more than a desperate performance by a man hoping to avoid the death penalty. Rana, who was indicted by a federal grand jury under 12 counts on February 15 last year for planning the attacks, providing material support to LeT to carry out the attacks and guiding Headley in scouting targets in Mumbai in the process. Arrested in Chicago over the Mumbai attacks, Rana had claimed that he provided ‘material support’ to 26/11 terrorists at the behest of Pakistani government and ISI.

If convicted, Rana faces a possible life sentence. While Headley has pleaded guilty, Rana has not pleaded guilty.

In pre-trial motions, Rana's lawyers proposed defending his actions by arguing that he believed Headley was working on behalf of ISI, not terrorists.

Headley testified to a grand jury that he had told Rana about ‘my meetings with Sajid and others in Lashkar’ and ‘how I had been asked to perform espionage work for ISI,’ court records show.

"I explained to him that the immigration office would provide a cover story for why I was in Mumbai," Headley said, according to court records.

Three of the suspected conspirators named in the indictment are ISI officers, court records showed. Headley - who changed his name from Daood Gilani so he could hide his Pakistani heritage - joined LeT in 2002, attending terrorist training camps five times over the next three years. He began working with an Al Qaeda-linked group in Pakistan called Harakatul Jihad-Islami on the Danish plot after LeT became distracted with the final planning for the Mumbai attack, a plea agreement said. Rana's trial is expected to last about four weeks.