Police say "road rage" led to a federal agent's death in South Florida, an area known for its bad driving habits.

Police said Thursday that James Patrick Wonder, 65, shot customs agent Donald Pettit in the head earlier this week after a confrontation erupted on the streets of Pembroke Pines.

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Police say Wonder was on his way to a dialysis appointment when he and Pettit, 52, who also was driving, exchanged obscene gestures.

Wonder pulled into a busy post office parking lot, and Pettit followed. The men began arguing and Wonder pulled a handgun from his waistband and shot Pettit once in the back of the head, according to Police Cmdr. Mike Segarra.

Rude drivers who chat on cell phones and speed through red lights have earned Miami the title as the U.S. city with the most road rage for several years now, according to a national survey.

On Thursday, police said Wonder checked into a hospital for personal medical reasons.

Sgt. Bryan Davis said Wonder was hospitalized after being questioned by police, but he could not release further information about his condition or why he was hospitalized. Authorities say he was at a dialysis center when he was caught.

Wonder is charged with first-degree murder. Pettit's 12-year-old daughter Gabriella Pettit witnessed the shooting.

Police say her detailed description of the shooter, which helped them draw and release a sketch, as well as an anonymous tip led to the suspect's arrest.

Wonder tried to cover his tracks, Segarra said, greasing his hair to make it darker and renting a car to drive to dialysis rather than using the one he was in when he got into the argument with Pettit.

The weapon used in the killing was confiscated, according to Segarra.

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