Italian border police are looking for a truck driver who is shown on a widely circulated video whipping female migrants after he found them in the back of his truck near the French border, officials said Wednesday.

Smugglers loaded the 12 Eritrean women on the truck at a rest stop near the French border on Monday while the trucker was having lunch, according to authorities. The women allegedly paid 100-150 euros ($110-1$65) to be transported across the border, but authorities believe the truck driver was unaware of their presence.

Once closed inside the truck, the women apparently started agitating due to the heat, with outdoor temperatures over 30 degrees C (86 F), drawing the driver’s attention, city officials said.

The video made by a witness — who asked not to be identified — shows the man striking at the woman with the hardware end of a cargo strap as they descended one by one. At one point, one of the women stood firm, shielding others so they could pass without being struck. The last woman to exit tried to grab the strap from him.