Democracy activists denounced plans for a military funeral honouring Omar Suleiman, Egypt's former spy chief and the closest lieutenant of Hosni Mubarak — a key pillar of the ousted president's authoritarian regime and holder of so many secrets that he was known as "the black box."

Suleiman, 76, died Thursday in a U.S. hospital. The shadowy statesman was considered Mubarak's most trusted man, handling the regime's most sensitive issues like relations with the U.S. and Israel and the fierce battle against Islamists. Suleiman's spy agency was responsible for tracking and suppressing opposition groups at home.

Tall, thin and often shown in dark sunglasses, Suleiman was also Egypt's point man in co-operation with the United States against terrorism and was involved in the post 9/11 rendition program in which terror suspects snatched by the Americans were shipped to Egypt and other countries for interrogation, sometimes involving torture.

In one case in 2002, the U.S. asked Suleiman for DNA material from the family of Ayman el-Zawahri, the Egyptian militant who at the time was al-Qaeda's deputy leader and now heads the group.

"No problem, we'll get his brother, cut off his arm and send it over," Suleiman replied.

The Americans said just a blood sample would suffice, according to the account by author Ron Suskind in his book on the rendition program, The One Percent Doctrine.

During the 18-day uprising last year, Suleiman was appointed vice-president in a last-gasp attempt by Mubarak to save his political life as hundreds of thousands of Egyptians took to the streets demanding his ouster. But the desperate measures, including talks between Suleiman and the formerly outlawed Muslim Brotherhood, were unable to stave off Mubarak's overthrow.

In the end, it was an ashen-faced Suleiman who appeared on state TV on Feb. 11, 2011, and read a terse announcement of Mubarak's resignation and the military's seizure of power.

Suleiman's sudden death came weeks after a member of his top nemesis, the Muslim Brotherhood, succeeded Mubarak as president. The intelligence agency Suleiman headed for 20 years was central to the Mubarak regime's repression of the Islamist group.

Suleiman called 'an international butcher'

Now President Mohammed Morsi faces new woes from Suleiman — over his funeral.

Presidential spokesman Yasser Ali told the state news agency that Suleiman, who was a general in the military, should have a military funeral. That brought quick denunciations from activists against honouring a figure whom they consider stained by his regime role and who should have faced trial.

"Omar Suleiman is an international butcher," said rights lawyer Malik Adly. "All the time he was the pampered man of the regime, the old and the new. Even the Brotherhood is holding a funeral for him. Why? All the time he was never questioned despite so many lawsuits against him."

Activists on social networking sites Twitter and Facebook launched a campaign of "no to military funeral to Omar Suleiman." Adly said they planned a symbolic funeral for the revolution's "martyrs" would be held the same day as Suleiman's.

The Cleveland Clinic in Ohio, where Suleiman had been treated since Monday, said in a statement he died of "complications from amyloidosis, a disease affecting the heart, kidneys and other organs."

Egypt's state news agency MENA said earlier that Suleiman had suffered from lung and heart problems for months, and his health condition had sharply deteriorated over the past three weeks. It said his three daughters will accompany the body to be buried in Egypt on Saturday.

Suleiman largely vanished from sight after Mubarak's fall. But he re-emerged in April in a surprise but short-lived attempt to join the race for president. He said he was running to prevent the Muslim Brotherhood from coming to power, warning that it would turn Egypt into a religious state.

But he was disqualified on technical grounds along with two Islamist candidates, including the Brotherhood's initial contender.

Testified in Mubarak trial

He also testified in the trial of his former boss, Mubarak, who was eventually sentenced to life in prison for failing to stop the killing of protesters during the uprising. Suleiman denied Mubarak issued orders to shoot at protesters, but said the president did learn about the killings when he ordered the formation of an investigative committee. Mubarak supporters blame that testimony for bringing the conviction.

But rights activists insist Suleiman should have been tried as well, for the protester deaths and for activities during Mubarak's rule. Adly said Suleiman hid information that could have convicted Mubarak for directly ordering the killings.

"Suleiman himself is deeply involved. But no one brought him to justice, why? This is the thing we never know," he said.

Suleiman was born in Qena in southern Egypt and graduated from the military academy as an infantry officer in 1955. He rose through the ranks and became deputy head of military intelligence in 1987. He became military intelligence chief in 1991 during the Gulf War, when Egyptians fought alongside other Arab forces in the U.S.-led coalition that drove Saddam Hussein's military out of Kuwait.

He indirectly saved his boss's life when he advised Mubarak to take an armored Mercedes with him on a state visit to Ethiopia in 1995. Islamic militants there sprayed his convoy with gunfire as he drove from the airport after arrival, but Mubarak was unscratched.

But his name only became known to the public in the early 2000s when Mubarak began moving the most vital issues of state to Suleiman, including relations in the U.S. and Israel and dealings with the Israeli-Palestinian peace negotiations.

Hossam Sweilam, a former general who has known Suleiman since they were in the military academy together, said Suleiman's lack of political ambition helped him keep his job so long in a paranoid regime.

"There was no intelligence chief who survived that long but Suleiman," he said. Mubarak was known to fear and get rid of politicians who rise in prominence.

Still, his power made some view him as a potential successor to Mubarak. That created silent tension between Suleiman and the president's younger son, Gamal, who was seen as being groomed by his father as a successor.