PALATINE, Ill. (CBS) — A 30-year-old man has been charged with abducting his girlfriend’s son last week in Palatine.

William Cruz, of Palatine, has been charged with one count of aggravated kidnapping, according to Palatine police. He is accused of kidnapping 8-year-old Eriberto Perez on Thursday evening.

Perez was found unharmed in a traffic stop at 9:45 p.m. Friday near downtown Chicago. His mother, Erika Rivera, said Cruz told her he was taking Eriberto to pick up some doughnuts for the family Thursday evening.

eriberto Palatine Man Charged With Kidnapping Girlfriends Son, 8

Eriberto Perez, 8, was taken without permission by his mother's boyfriend, police say. (CBS)

Although Cruz is not Perez’s biological father, the boy’s mother allowed him to take the boy along, with the understanding he’d be back shortly.

But Cruz later told her in a cell phone call that the two were instead driving to a relative’s house in Chicago.

Rivera said her son sounded frightened over the phone.

“He sounded like scared, like (Cruz) told him, ‘Don’t say nothing,” she told CBS 2’s Suzanne Le Mignot.

Eriberto is Rivera’s oldest child. His father is deceased.

She said she had recently told Cruz she planned to leave him.

State police said Eriberto, once found, was taken to the hospital as a precaution. Cruz was taken into custody.

Court information for Cruz was not immediately available.

(The Sun-Times Media Wire contributed to this report.)

Watch & Listen LIVE