Ex-wife of attacker taken in for questioning

French police have taken in the ex-wife of the Nice attacker Mohamed Lahouaiej Bouhlel for questioning over his possible links to the Islamic State group. Bouhlel had been in trouble with the law repeatedly but was not on any terrorism watchlist. 

He has been described as a "weird loner" who "became depressed" when his wife left him. 

Investigators said they are seeking to establish Bouhlel's motives and looking into possible accomplices.