The teens - two 13-year-old boys and two 15-year-old boys - then ran away. But their images were captured by several surveillance cameras at the store and in the area, police said.
On Monday morning, Upper Darby police posted images of the suspects to their Twitter and Facebook accounts. That night, the parents of two of the boys brought their children to Upper Darby police headquarters for questioning after seeing their sons' images all over social media, Chitwood said.
"One set of parents were very cooperative," he said. "The other set brought him in because they knew it was him on the social-media page."
Chitwood said police worked with security guards at Upper Darby High School to identify the remaining two suspects.
All four boys were charged with robbery, assault and related offenses and remain at Delaware County's juvenile detention center in Lima. Their names are not being released, given their juvenile status.
The victim in the case did not require hospitalization for his injuries, police said.
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