One of the women arrested on Thursday is a daughter of the car’s owner, according to the Paris prosecutor’s office. The owner of the vehicle was arrested on Tuesday, but has since been released.

The car was not rigged to explode. The police found no detonator with the six gas cylinders — an empty one in the back seat and five full ones in the trunk — although they did find three jerrycans of diesel fuel.

A notebook with Arabic writing in it was also found in the car, according to the prosecutor’s office, which did not elaborate.

Amateur video footage showed the car parked with its hazard lights flashing. The district mayor said it sat that way for two hours before the police responded to a shopkeeper’s call about a suspicious vehicle.

Altogether, seven people are now in police custody in connection with the car. In addition to the three women arrested on Thursday, the police have arrested four other people from the Loiret area in central France — two brothers, ages 27 and 34, and their girlfriends, who are 26 and 29, according to the prosecutor’s office, which did not say how any of them might be linked to the Peugeot.

But all four are suspected of being “radical Islamists,” the prosecutor’s office said. One couple was arrested on Tuesday at a highway service area in southern France, and the other was arrested late Wednesday or early Thursday near the town of Montargis in Loiret.

Fears of an attack on large crowds in cities or at big events rose after a Tunisian man killed 86 people by driving a truck through crowds gathered to watch Bastille Day fireworks in Nice, France.