Omar Suleiman, who died Thursday, was a military man who fought in the 1967 and 1973 wars against Israel. However, he is best known for his role as Egypt's intelligence chief during the last 20 years of Hosni Mubarak's reign and for his brief stint as vice president during the 18-day uprising in 2011.

Suleiman was the mastermind behind Mubarak's attempts to crush both militant and peaceful Islamist groups in Egypt and the man who persuaded Mubarak to improve political and economic cooperation with Israel, whose leadership viewed Suleiman as a man they could do business with.

During the last ten years of the Mubarak era, Suleiman moved out of the shadows into a position in which he was essentially running Egypt's foreign policy. In a number of key national security areas, such as relations with Israel, Sudan and the Nile Basin countries, the foreign ministry played a secondary role behind Suleiman.

The spy chief was accused by activists of participating in the torture of terrorist suspects rendered to Egypt by the US as part of the so-called War on Terror.

He was a key figure in relations with Israel and Palestine and had a good relationship with Hamas until it won power in Gaza in 2005. At that point he turned against the Islamist group and colluded with Israel to isolate the impoverished strip of land.

Suleiman cemented his close relationship with the former president when he insisted the latter travel in an armoured car whilst on a visit to Addis Ababa for an African Union summit in 1995. The advice saved Mubarak's life when assassins peppered the car with bullets.  

According to a Suleiman aide, from that day on Mubarak's trust in his intelligence chief's abilities grew greatly, making him one of his closest aides and confidantes.

The same aides said it was Suleiman who dared to tell Mubarak that his plan to install his son Gamal as his successor was very unpopular among the public and was damaging to Mubarak's own credibility and legitimacy.

"Mubarak would have listened to him if it hadn't been for pressure from businessmen close to Gamal, and Suzanne Mubarak [Gamal's mother and Hosni's wife]," said an aide.

Since his withdrawal from the limelight upon Mubarak's overthrow, Suleiman was still called upon for advice by former aides, some of whom were partially responsible for his 11th hour decision to run for president in early April.

Suleiman was said by aides to be unsure whether to run for president, but was eventually convinced by the idea that only he could 'save' the country from an Islamist takeover.

Suleiman's candidacy was perceived by many as a move coordinated with the Supreme Council of the Armed Forces, which ruled the country after Mubarak stepped down.

Large anti-Suleiman demonstrations took place after his candidature was announced but the Supreme Presidential Electoral Commission later excluded him from the race because he had not completed the paperwork required to become an official candidate.

After he was excluded from the race he went to live in the United Arab Emirates.

Yet the highlight of Suleiman's career was when he announced Mubarak's decision to step down from office on 11 February 2011.

His death puts a lid many on state secrets, particularly those relating to the 25 January Revolution.

"He never spoke much and he declined offers to write his memoirs; he thought he was not at liberty to tell the story," said one of Suleiman's closest aides.

The former spy chief's body is expected to arrive in Cairo on Thursday afternoon and preparations are underway for a military funeral on either Friday or Saturday.