Approached by Britain’s MI6 while reporting on Nigeria’s Biafra War, he mined his experiences for literary inspiration.

Best-selling British novelist Frederick Forsyth, author of about 20 spy thrillers, has died at the age of 86.

Forsyth, who was a reporter and informant for Britain’s MI6 spy agency before turning his hand to writing blockbuster novels like The Day of the Jackal, died on Monday at his home in the village of Jordans in Buckinghamshire, said Jonathan Lloyd, his agent.

“We mourn the passing of one of the world’s greatest thriller writers,” Lloyd said of the author, who started writing novels to clear his debts in his early 30s, going on to sell more than 75 million books.

“There are several ways of making quick money, but in the general list, writing a novel rates well below robbing a bank,” he said in his 2015 autobiography, The Outsider: My Life in Intrigue.