French prosecutors are investigating whether the man who killed a policeman in Paris had accomplices and links to terrorist groups, as France prepares to vote in the closest, most volatile election in years.
So far the authorities appear to be drawing a blank on possible links between Karmi Cheurfi and terrorist groups.
They do not know whether the 39-year-old had accomplices as he carried out the shooting on the iconic Champs Elysee boulevard.
Cheurfi had a long criminal history but police believe he showed no sign of radicalisation. Authorities would have had plenty of opportunity to notice extremist tendencies in his frequent brushes with the law and periods in custody.
Islamic State said it was behind the attack but cast doubt on that claim by identifying the gunman by the wrong name and saying he was Belgian, when he was French.
However, a note professing allegiance to IS was found near the body of the dead gunman shortly after the shoot-out.
On Saturday, there was brief panic as a man with a knife was arrested at Paris' Gare du Nord station.
No one was injured but travellers abandoned their luggage as officers surrounded the man.
None of this will reassure jittery French voters as they ponder their electoral options in a climate of uncertainty and fear. The attack has made security an even more prominent issue in the presidential election.
:: Parisians fear attack may impact election
France was already obsessed with the threat of terror attacks and the authorities' apparent failure to stop them happening.
In such a closely fought, volatile race, the attack is certain to have had an impact.
This election had been all about about change and disrupting the status quo in France, but the attack could change all that.