Q&A: Tahawwur Rana case

Chicago businessman Tawwahur Rana has been sentenced to 14 years in prison for aiding a Pakistani Islamic militant group blamed for the 2008 Mumbai attacks.

The trial was closely watched for what it might reveal about Pakistan's role in the global fight against terrorism.

Who is Tahawwur Rana?

Tahawwur Hussain Rana, 50, grew up in Pakistan and following his medical degree joined the Pakistani Army's medical corps. He and his wife, also a doctor, became naturalised Canadians in 2001.

Before his arrest in 2009, Rana lived in Chicago, running several businesses, including an immigration and travel agency.

Three years earlier he helped his childhood friend David Headley open a branch of the immigration firm in Mumbai. Prosecutors argued the office was set up to scout for possible terrorist targets in the city.

Headley - who pleaded guilty to identifying locations for the Mumbai attacks - was a key prosecution witness. He admitted he had links to the militant organisation blamed for the attacks, Lashkar-e-Taiba, and said he had links to the Pakistani intelligence service ISI.

What was he convicted of?

Rana faced 12 charges, including helping to kill American citizens. He was also charged with providing a cover for Headley and of passing messages between his former friend and a man known as "Major Iqbal", who some believe is part of Pakistan's Inter-Services Intelligence agency.

Rana was convicted of providing material support to Lashkar-e-Taiba and for his role in an aborted plot against a Danish newspaper.

But the Pakistani-born Canadian was cleared of charges of direct involvement in the Mumbai attacks, which killed more than 160 people, including six Americans.

How was he arrested and when?

Rana and Headley were arrested in October 2009 for allegedly plotting to attack the offices of Jyllands-Posten newspaper, which had published cartoons of the Prophet Muhammad.

The federal court in Chicago has charged four other men in relation to Rana and Headley's case. They were identified as Captain Iqbal, Sajid Meer, Abu Qahafa and Mazhar Iqbal, all Pakistani nationals. Only Mazhar Iqbal was arrested in Pakistan.

What was David Headley's role?

David Headley's testimony connected his actions to the ISI, although Pakistan has repeatedly denied any such links.

He confessed to being involved in the conspiracy to attack Mumbai at the behest of some of his associates in Pakistan. He used to meet the four men charged and named by the Chicago court with taking lead roles in the Mumbai attacks.

According to court documents, Headley made several visits to Mumbai to survey the locations for attacks. After each of his visits to Mumbai he went to Pakistan and met his handlers. It is alleged that on their advice he opened an immigration and travel office, called First World, owned by Rana.

How reliable a witness was Headley?

Pakistan accuses him of being a liar and has flatly denied any allegations that implicate the ISI.

Headley gave a detailed account of his claimed involvement with some people in the ISI - testifying the agency had provided military and moral support to LeT.

The defence attempted to discredit Headley, who avoided the death penalty and extradition in return for his testimony, and argued he misled Rana.

What does it mean for US-Pakistani ties?

The trial began as Pakistan's intelligence services were under fire for failing to detect Osama Bin Laden, killed by US forces killed in May 2011 outside Islamabad.

But the US government avoided naming the ISI in the charges, a "tactical" move according to Sebastian Rotella, a ProPublica journalist who has written extensively about the trial.

By not naming the ISI the US is sending a "tough signal to Pakistan but pulling the punch", says Rotella. "It doesn't want to give the impression that it is blaming the entire institution."

Christine Fair, a professor and terrorism expert at Georgetown University, said the trial was a "big deal" before Osama Bin Laden was killed, "but it is an even bigger deal now because in part there is so much frustration across the US government with Pakistan".