MAHWAH -- A school bus driver from Paterson was arrested Thursday after a 12-year-old girl told a therapist the two had shared explicit photos of themselves, Chief James N. Batelli said.

Eddie Toste-Sanchez, who works for FSZ Transportation in the Wantage school district, transported the girl between her home and a private school in Mahwah. The girl revealed during a therapy session Thursday that a "loving" relationship was developing between she and Toste-Sanchez, Batelli said. The girl's mother had earlier reportedly expressed concern to a school therapist about the relationship between the two.

Batelli also said the girl had become Facebook friends with the 41-year-old Toste-Sanchez, who had recently been hired by the bus company. Toste-Sanchez also showed the girl pictures of his genitalia while they were alone on the bus, and she showed him nude pictures of herself, investigators said.

Toste-Sanchez was taken in for questioning Thursday afternoon, when he allegedly admitted to police that the two had viewed the photos of each other. Toste-Sanchez and the victim's mother authorized police to search their cell phones, where the photos were found, Batelli said. The phones were being examined by the Computer Crimes Unit of the Bergen County Prosecutor's Office.

Toste-Sanchez has been charged with sexual assault of a juvenile under 13 and endangering the welfare of a child, which was upgraded to a second-degree offense because of Toste-Sanchez's role as an authority figure to the girl. He was being held at the Bergen County Jail on $100,000 bail.

Paul Milo may be reached at pmilo@njadvancemedia.com. Follow him on Twitter @PaulMilo2. Find NJ.com on Facebook.