Omar Sheikh, 27, was born in London, attended the London School of Economics and was a close associate of Maulana Azhar Masood - founder of the banned Jaish-e-Mohammad (JEM) group, which India blames for an attack on its parliament in December 2001.
His father, Saeed Ahmed, was a Pakistani clothes merchant from Wanstead in east London.
Omar Sheikh was reportedly a contemporary of England cricket captain Nasser Hussain at the private Forest School, in Snaresbrook.
He moved to Lahore and studied at the elite Aitchison College for three years before returning to Forest School in the Sixth Form.
After passing four A-levels with good grades, Omar Sheikh enrolled at LSE in October 1992.
But he left before the end of his first year of an undergraduate degree in statistics.
Reports suggest he visited Bosnia as an aid worker and soon after, he moved to Pakistan.
A BBC reporter - Zubair Ahmed - interviewed a young Omar Sheikh in 1994 as he lay in hospital near Delhi.
The 20-year-old said he had returned to Britain from "holy war" in Bosnia but had then left again to fight for Indian and Kashmiri Muslims.
He was arrested by Indian police in 1994, accused of kidnapping three Britons and an American in India.
In 1999, while serving a prison sentence for terrorist offences, an Indian Airlines plane was hijacked to Kandahar in Afghanistan.
And in exchange for the 155 hostages on the plane, Omar Sheikh was freed from jail.
He married in December 2000 and became a father in November 2001.
Spotted
But he left his Lahore home with his wife and the two-month-old baby four days before Mr Pearl was abducted.
People who knew Omar Sheikh when he lived in Britain were shocked when allegations that he was involved in the journalist's abduction were first made.
George Paynter, who was his economics tutor at Forest School, said: "I'm horrified. The chap we knew was a good all round, solid and very supportive pupil.
"We are just absolutely stunned that he might be involved in these activities."
Mr Paynter added: "He was in the premier league of students, there was absolutely nothing there, no sign whatsoever of this.
"He wouldn't have been here if there was. He was a nice bloke and very respectful."
Neighbours of Omar Sheikh's parents said the family had lived in the area for nearly 20 years.
One neighbour, in Deyne Court Gardens, Wanstead, who did not wish to be named, said he last saw Omar Sheikh in early 2001 when he was home for a visit.
He said: "It's been in the local papers. I saw him when he was released home from prison about a year ago. I've never spoken to him but I have seen him several times."