CHICAGO (CBS) — More than 700 people attended a funeral service in Dolton for the 15-year-old boy with autism who was shot to death February first by Calumet City Police.

Stephon Watts’ mother cried over his casket for 20 minutes before the service, at New Zion Christian Fellowship Church. Senior Bishop Lance Davis said Stephon’s father, Steven Watts, could not bring himself to leave the car and enter the church until the service was well underway.

“The father’s more concerned and remorseful about the fact that he opened the door for the police department,” Davis said.

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The elder Watts witnessed the shooting.

More than a dozen floral arrangements stood at the front of the church, three of them on the casket. One was in the shape of a red-and-white heart.

Former Northwestern and NFL linebacker Napoleon Harris donated much of the funeral costs

The Illinois State Police Public Integrity Unit continues to investigate the case. Steven Watts has said that he called Calumet City Police on their non-emergency line only because an employee at a local hospital said he had to file a police report before bringing Stephon for treatment.

Steven Watts has said that the teen was using a butter knife to try to pry open a locked cabinet when police arrived. His father had placed the computer in the cabinet because the boy was acting out. Police have said that Stephon appeared to be coming at them with the knife before he was shot by two different officers, even though one of the officers also carried a Taser gun.

Watts said the family had called Calumet City police at the advice of health care professionals at least 10 previous times without a problem.