Updated 08/12/12 – 4:58 p.m.

MAYWOOD, Ill. (CBS) — A motorcycle accident involving a Chicago police officer ended with the off-duty cop shooting the father of the girl he had hit, when that man attacked him after the crash.

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Authorities said Christopher Middleton, 26, brutally beat a 43-year-old off-duty Chicago cop, after the officer struck Middleton’s 4-year-old daughter with his motorcycle late Saturday night.

CBS 2’s Derrick Blakley reports, outside the Maywood house he was visiting yesterday, emotions were still raw for Christopher Middleton’s extended family.

Asked how they are dealing with the loss, his cousin Mathis Hoskin said, “We’re dealing with it pretty strong right now. … I can’t believe he’s gone.”

Middleton was shot to death by an off-duty Chicago police officer, after the cop’s motorcycle hit Middleton’s 4-year-old daughter, who was crossing busy First Avenue.

Around 10:30 p.m., as the eight-year veteran officer was riding his motorcycle north on First Avenue, the girl was returning from a jerk chicken shop with her 18-year-old cousin when they were both struck by the officer’s motorcycle.

Police said the officer did all he could to avoid more serious injuries, but Middleton was furious that his daughter had been struck, and attacked the officer.

Middleton’s cousin, Cordell Haggard, said, “While he was on top of the guy, fighting him, the guy somehow managed to reach for his weapon, and he fired it, and shot him right in his groin.”

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Middleton’s family insisted he never knew he was attacking an off-duty cop.

“He never let anyone know that he was an officer until after he shot him,” Haggard said.

That’s a point authorities strongly dispute.

Maywood village spokesman Larry Shapiro said the officer announced he was a cop.

“This is what we were told. Our investigators indicated that that was in fact true,” Shapiro said.

Investigators continued knocking on doors on Sunday, gathering facts about the incident, and Middleton’s relatives continued to insist he didn’t overreact – police did.

His uncle, Darrell Davis, said, “I don’t believe he used necessary force. … If he was a police officer, with his experience, he could have calmed the situation in a better way than he dealt with it.”

Four year-old Tania Middleton, the girl injured by the motorcycle, was treated and released from Loyola University Medical Center. Her 18-year-old cousin, John Passley, was also hit by the cycle, but didn’t require medical attention.

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Passley also allegedly participated in the beating of the officer, and was being held by Maywood police.