Philadelphia (CNN) -- Bailey O'Neill's parents just wanted him to see his 12th birthday.
The next day, they took him off life support.
The fatal injuries that led to Bailey's death Sunday were the tragic consequences of bullying at school, his parents said.
Rob O'Neill said his son was punched during a bullying incident at recess at Darby Township School in January. He said Bailey suffered a fractured nose, a concussion and seizures from the attack and was in a medically induced coma.
"We're all overwhelmed and saddened," he said. "I don't ever want another kid to end up like Bailey. It's such a shame."
But Philadelphia-area detectives are still investigating whether the incident was, in fact, bullying or an altercation on the playground.
"This is an ongoing, active criminal investigation," said Emily Harris, spokeswoman for the Delaware County district attorney's office. "We are reviewing all aspects of the school incident."
Surveillance footage shows three students in the schoolyard, including Bailey. There was one "striker," Harris said.
Investigators are waiting for autopsy results that will become part of the investigation.
The Southeast Delco School District issued a statement Monday offering its condolences to Bailey's family and friends.
"Our school community is deeply saddened by this loss," Superintendent Stephen D. Butz wrote.
"Additional counselors have been made available to assist our students and staff with the emotions around the death of Bailey. The school district continues to work with local authorities in their investigation into the cause of Bailey's death."
Funeral arrangements for Bailey are pending, with services expected later this week.