A man suspected to have killed a French policeman and his partner in a terror-linked attack had been sentenced in 2013 for taking part in a jihadist organisation with links to Pakistan, sources said Tuesday.

They identified him as Larossi Abballa, 25, adding that he had been sentenced to a three-year term -- six months of which were suspended -- for "criminal association with the aim of preparing terrorist acts," in a trial with seven other defendants.

A policeman and his partner were killed at their home in the Paris suburb of Magnanville late Monday, in an attack by a man claiming allegiance to the Islamic State group, sources close to the investigation said earlier.