Former Malian prime minister Soumeylou Boubeye Maiga was arrested on Thursday as part of a corruption investigation, his lawyer Kassoum Tapo said.
Maiga, 67, was a close ally of former President Ibrahim Boubacar Keita, who was overthrown by strongman Colonel Assimi Goita in August 2020.
A member of the Supreme Court, who requested anonymity, also told AFP that Maiga had been arrested as part of a judicial investigation into "damage to public assets."
He is being questioned in connection with the allegedly fraudulent purchase of a presidential plane in 2014 when Maiga was serving as defence minister.
Mali's government auditor investigated the purchase and found that officials had embezzled public money by overbilling for the plane.
A senior Malian civil servant, who declined to be named, suggested that many other figures could get caught up in the probe.
"This could be the beginning of a big shakeout," he said.
Maiga, who also previously served as foreign minister and head of the intelligence service, is believed to be well connected in Mali's security establishment and has been accused of financing pro-state militias.
He was appointed Keita's prime minister in 2017 but resigned in April 2019 over a massacre in the centre of the country that left 160 people dead.
Mali has been struggling to contain a jihadist insurgency that first emerged in the north, before spreading to the centre of the country and neighbouring Burkina Faso and Niger.
Thousands of people have been killed and hundreds of thousands have been displaced in the conflict, crippling an already impoverished country.
Army officers led by Goita deposed Keita last year after weeks of protests over his failure to defeat the jihadists and anger over perceived government corruption.
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