NICE, France, July 17 (UPI) -- French authorities arrested two additional suspects -- a man and a woman -- Sunday in connection with the terror attack that killed 84 last week.
Agnes Thibault Lecuivre, a spokeswoman for the prosecutor, said the two were taken into custody for questioning, but gave no details.
Five other people were questioned and four remained detained. The attacker's ex-wife was released from custody Sunday morning.
Mohamed Lahouaiej Bouhlel, 31, drove a 19-ton truck almost more than a mile through revelers on Promenade des Anglais to watch the Bastille Day fireworks on the Mediterranean city's waterfront Thursday. He was shot to death by police.
More than 200 were injured and 75 remain hospitalized, including 18 in life-threatening condition, Health Minister Marisol Touraine said Sunday. Five children were in intensive care.
A third U.S. victim has been identified by the FBI as University of California at Berkeley student Nicolas Leslie. He had been missing since the Thursday attack and was confirmed dead Sunday.
Leslie, 20, was an environmental science student in the school's study abroad program. He was one of four UC Berkeley students in the attack. Two others have broken legs and another has a broken foot.
A Texas father and son were also killed in the Nice attack.
Another UC Berkeley student was killed in the terrorist attack in Dhaka, Bangladesh two weeks ago.
New details emerged Sunday about the attacker.
Bouhlel scouted out the promenade twice before the attack -- on Tuesday and Wednesday, the prosecutor's office told NBC News. Surveillance footage shows him in the truck he used to carry out the carnage, he said.
Interior Minister Bernard Cazeneuve told reporters Saturday that Bouhlel "appears to have become radicalized very quickly."
He was "entirely unknown by the intelligence services, whether nationally or locally," French prosecutor Francois Molins said.
Police knew about him because of threats, violence and thefts over the past six years. He received a suspended six-month prison sentence this year after a violence with a weapon conviction, authorities said.
Bouhlel's father, who lives in Tunisia, said his son had multiple nervous breakdowns and volatile behavior, CNN reported.
The Islamic State's media group, Amaq Agency, said an IS "soldier" carried out the attack.
In a statement Saturday, it said "the person ... carried out the operation in response to calls to target nationals of the coalition which is fighting the Islamic State."
Bouhlel, a resident of Nice, had a permit to live and work in France. He was born in Tunisia.