Rajapaksa, 80, faced questions for more than two hours from the Bribery Commission in Colombo, where thousands of supporters gathered outside the premises.

The probe centres on claims that funds from a multi-million-dollar deal involving European aircraft manufacturer Airbus were channelled to senior Sri Lankan officials.

A spokesman for Rajapaksa denied the allegations and the former leader has repeatedly dismissed corruption claims against him as politically motivated.

The former chief executive of SriLankan Airlines, Kapila Chandrasena, told investigators in March that he handed nearly half a million dollars in kickbacks to Rajapaksa, according to officials.

He was found dead at a relative’s home on Friday, shortly before he was due to be rearrested. The cause of his death has not yet been established.

Chandrasena, 61, was arrested in March and had been released on bail last week.

His wife, who is also a co-accused in the case, has reportedly fled the country.

A joint investigation by US, British and French authorities previously found Airbus had agreed to pay about US$16 million in bribes in Sri Lanka, with US$1.7 million routed to Chandrasena before the scandal was uncovered.

The payments were linked to a US$2.3 billion deal for SriLankan Airlines to purchase 10 Airbus aircraft that required cabinet approval during Rajapaksa’s presidency from 2005 to 2015.

According to submissions made in court, Chandrasena initially told investigators he had paid Rajapaksa 60 million rupees (US$461,000 at the time) in three instalments in 2013. He later retracted the statement, claiming it had been made under pressure.

SriLankan Airlines, once a flagship state carrier, has accumulated losses estimated at 596 billion rupees, and repeated attempts to privatise the debt-laden airline have failed.