The officer pulled over 34-year-old Jaime Jimenez-Juarez on Niblock Alley around 3:45 p.m., the department said.
Jimenez-Juarez was wanted on a misdemeanor DUI warrant from state police, authorities said.
The 34-year-old gave over his ID, but fled on foot when the officer tried to arrest him, police said.
During the pursuit, the officer fell down a nearby hill and hit his head on a "hard surface," knocking him unconscious, according to the department. He was rushed to an area hospital with serious injuries but had been discharged by Thursday, Sept. 21.
Jimenez-Juarez is now sought on charges of felony aggravated assault, evading arrest, and related counts, said Oxford police.
Anyone with information should call the department at 610-268-3171 or submit an anonymous tip through Chester County Crime Watch.
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