Chan Kosal (centre), who died on Wednesday of lung cancer, at the Phnom Penh Municipal Court last year. Photograph: Pha Lina/Phnom Penh Post

Convicted former police official and ex-Chea Sim adviser Chan Kosal had died of lung cancer in his cell at Prey Sar prison on Wednesday, a police official said yesterday.

Chan Kosal, 62, a former lieutenant-general, was convicted of serious fraud last December after a court found he had served as middleman in a land concession deal between his boss, Senate president Chea Sim, and a Malaysian businessman, accepting a sizeable commission in the process.

“He had lung cancer and other epidemic diseases,” Sun Lean, chief of the Ministry of Interior’s Prey Sar Correctional Centre, said. “He died from lung cancer after he had a lung operation last month at the Calmette Hospital in Phnom Penh.”

Sun Lean said Chan Kosal’s condition had worsened quickly after the operation.

Chan Kosal was arrested last September along with four other members of Chea Sim’s cabinet in a conspiratorial scandal that left the senate president – who was re-elected in March – relatively unscathed.

Their arrests were based on a complaint by Chea Sim himself, with approval from Prime Minister Hun Sen.

Tep Mony Cheath, Chan Kosal’s former defence lawyer, expressed regret at the death of his client, saying that although Chan Kosal had been accused of serious fraud, he was a generous person who had contributed a substantial amount of his own money to development projects, poverty reduction and services for the poor.

In 2011, Chan Kosal gave more than $200,000 of his own money to build roads in Svay Rieng province, he said, adding that he also persuaded many foreign investors to participate in Cambodian anti-poverty projects.

Members of Chan Kosal’s family could not be reached for comment.

To contact the reporter on this story: Buth Reaksmey Kongkea at [email protected]