Members of the scientific police inspect a burned car at the scene of an incident in which it rammed a gendarmerie van on the Champs-Elysees Avenue in Paris, France, June 19, 2017. REUTERS/Charles Platiau

PARIS (Reuters) - A man who rammed his car into a police van near Paris’ Champs Elysees avenue on Monday had pledged allegiance to Islamic State militants, a source close to the investigation said on Tuesday.

The source said the man, who died in the attack, had given a letter to his brother-in-law announcing his support for the group that controls parts of Syria and Iraq.