When Miami Beach police cuffed Brazilian race car driver Joao Paulo Escudero Mauro for the car wreck that killed a pedestrian on Collins Avenue, the arrest report laid out clear-cut evidence.

Mauro was driving at a reckless speed when his Mercedes Benz hopped a curb and struck Russell Knudson on Jan. 19, 2012, detectives said. And Mauro was driving drunk and had a baggie of cocaine, according to the report.

But on Monday, as prosecutors abandoned the DUI and vehicular manslaughter charges against Mauro, it became apparent the evidence did not support the investigators’ case.

A toxicology report — finished five months after the arrest — showed Mauro had not used any illegal drugs and had a blood-alcohol well below the legal limit. The cocaine baggie was not found on Mauro’s person, but possibly discarded on a pavement crowded with people that night.

And evidence later showed Miami Beach police miscalculated the speed Mauro was driving. A traffic accident expert — and the car’s own internal computer system — showed Mauro was driving closer to 38 miles per hour in a 30-miles-per-hour zone.

The glaring holes in the evidence forced prosecutors to drop the three felony charges, and Mauro pleaded guilty to a traffic citation.

“Based on the facts, the science of accident reconstruction, and the toxicology, the only ethical and legal way to resolve this case was by reducing the charges to careless driving resulting in death,” Miami-Dade prosecutor Suzanne Von Paulus wrote in a memo released Monday.

As part of Mauro’s plea, he must complete 100 hours of community service, plus give up his driver’s license for 10 years. Mauro, 21, also will have to make a yearly donation to Mothers Against Drunk Driving.

Mauro, who wrote an apology letter to the Knudson family, also will have to view the crime scene photos.

Knudson’s family sued and settled for an undisclosed sum with Mauro, who raced in the North American Rolex Sports Car series.

Knudson, 45, who lived in Miami with his brother, Steve, work worked as a cook at a nearby the nearby Carraba’s Italian Grill. That night, he was loading his bicycle onto the back of a friend’s car on the 3900 block of Collins Avenue when he was struck by Mauro’s Mercedes SUV.

“Mr. Mauro feels terrible for the Knudson family’s loss and his heart-felt sympathy goes out to them,” his attorneys, Gus Lage and John Priovolos, said in a statement. “This is a tragedy Mr. Mauro will carry with him for the rest of his life.”

“However, Mr. Mauro also looks forward to carrying on with his life and returning to Brazil once he has completed all of his court-mandated obligations here in the United States.”

Mauro, who cooperated with Miami Beach police, explained that he swerved suddenly to avoid a car in front of him. His SUV jumped the curb, struck Knudson and toppled a light pole.

He admitted he had enjoyed a drink — but only one glass of champagne.

Several witnesses with Mauro told police he was not speeding. But one woman with Knudson said she believed the Mercedes was traveling at excessive speed.

Miami Beach police arrested Mauro, who also had a Brazilian ID that appeared to have a wrong birth date. At an initial bond hearing, a prosecutor argued that he could flee to Brazil, where he would be beyond the reach of U.S. law.