(CBS) – An alert parent is credited with helping police arrest a Chicago man who allegedly grabbed a Fenton High School student and threatened her with a knife Friday.

School officials and Bensenville police say the outcome could have been very different if not for that parent, CBS 2’s Roseanne Tellez reports.

The 16-year-old student was walking on West Green Street in Bensenville around 7:30 a.m. when a man with a pocketknife grabbed her by the arm, she told authorities.

School principal Todd Leden says an alert parent knew something was wrong — and acted by calling 9-1-1.

The girl, meanwhile, ran to the school building, say police, who quickly took a suspect in custody.

Mario Anthony Booker, 24, was charged with attempted aggravated kidnapping, attempted kidnapping, unlawful restraint and aggravated assault.

“We’re thrilled with the way that things turned out,” school superintendent Kathie Pierce says. “The girl is safe. She’s calm, cool and collected. I was so shocked at the way she handled the situation.”

One caution: The student was wearing headphones on her way to school. The school superintendent says that’s why she may not have heard the attacker approach, and why it may have made her a target.