Al Qaeda leader Ayman al-Zawahiri, who was killed by a U.S. drone strike in Kabul, seemed harmless to neighbours when he was a young man growing up in a leafy Cairo suburb.

"Years went by, and then all of a sudden we heard about Ayman al-Zawahiri doing all these things, he became something we would have never imagined," said Attia Salama, his former neighbour in the upscale Cairo suburb of Maadi.

"He used to be quiet, no one used to pay attention to him at all. Our experience with him and his family was totally normal, we had no idea he was with that movement."

Zawahiri, an Egyptian surgeon, went on to become the leader of one of the country's most feared militant groups, Islamic Jihad, convincing disillusioned young men to turn against the U.S.-backed state.

A lawyer for the Zawahiri family could not immediately be reached for comment on Tuesday.

Zawahiri orchestrated a campaign in the mid 1990s to overthrow the government and set up a purist Islamic State. More than 1,200 Egyptians were killed.

Egyptian authorities mounted a crackdown on Islamic Jihad after an assassination attempt on President Hosni Mubarak in June of 1995 in Addis Ababa.

The greying, white-turbaned Zawahiri responded by ordering a 1995 attack on the Egyptian embassy in Islamabad. Two cars filled with explosives rammed through the compound's gates, killing 16 people.

Zawahiri did not emerge from Cairo's slums, like others drawn to militant groups who promised a noble cause. Born in 1951 to a prominent Cairo family, Zawahiri was a grandson of the grand imam of Al Azhar, one of Islam's most important mosques.

Zawahiri was raised in Maadi suburb, a place favoured by expatriates from the Western nations he railed against. The son of a pharmacology professor, Zawahiri first embraced Islamic fundamentalism at the age of 15.

Zawahiri was killed on Sunday in Kabul, Afghanistan, by a U.S. drone missile, officials in Washington said.

CLIMBS AL QAEDA RANKS

His former neighbour Salama stood on a typical Egyptian street filled with vegetable vendors, cafes, mechanics and buses as he reflected on Zawahiri's life before he climbed the ranks of Al Qaeda determined to terrorise the United States and other Western countries.

Zawahiri's friends used to come by and then they would all go and pray, Salama said.

"We were surprised to see the state security coming in two cars and taking him and his brother Hussein and detaining them," said Salama, referring to state security agents working for Mubarak.

"He used to go around and pray and go to his clinic. And then all of sudden it changed, and security came and got him."

Zawahiri disappeared after he was released from prison and eventually headed to Afghanistan to fight Soviet occupation troops. Determined to keep tabs on Zawahiri, security forces would pass by Maadi and question his father and mother about his whereabouts.

He would go on to become the mastermind of some of Al Qaeda's most spectacular attacks. He had a $25 million bounty on his head and helped to coordinate the Sept. 11, 2001, attacks on the United States that killed nearly 3,000 people.

Another acquaintance from the neighbourhood, Hassan Izzeldin, said his family were well-known, decent people.

"He chose this path for himself, and he is the one to blame for his end," he said.