Frenchpolice have arrested four people over an explosion in the heart of the southeastern city of Lyon last week which injured 13 people, authorities said Monday.
The suspected bomber, a 24-year-old Algerian citizen, was arrested along with his mother, his father and another Algerian student who is a family friend, according to Paris prosecutors.
The suspect is an IT student previously unknown to police, Lyon's mayor Gerard Collomb said.
Prosecutors had on Friday opened an investigation over "attempted murders linked to a terrorist organisation".
Sources close to the investigation suspected the explosive was acetone peroxide, or APEX, a volatile compound used in deadly Paris attacks that happened on November 13, 2015.
No one has claimed responsibility for the Lyon blast.
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