NEW YORK (CBSNewYork) — Police in Brooklyn say a good Samaritan helped chase down a suspected hit-and-run driver, who allegedly mowed down an elderly man.

Authorities announced the arrest of 47-year-old Hernan Diaz Thursday night.  Diaz faces charges of DWI, vehicular assault and leaving the scene of an accident.

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Police said the 90-year-old man was hit by a truck at Metropolitan Avenue near Orient Avenue around 11:30 a.m. Thursday morning in Williamsburg.

Authorities said the Diaz kept on going and neighbors were stunned.

A shaken up Dori Martin described what she saw outside her brownstone earlier in the day.

“I saw the man on the floor,” she told CBS 2’s Ann Mercogliano. “The police helped him.”

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The victim was rushed to Bellevue Hospital with serious trauma. Police said it is unclear if he was crossing the street at the time or if he was in the crosswalk.

“It’s a sin for them and hit-and-run, I don’t go for that. They wouldn’t like it if their parents got hurt. It’s a shame,” Dorothy Belotto said.

Diaz didn’t get very far and was taken into custody a few blocks away at Meeker Avenue and Lorimer Street, police said.

Mercogliano reported that police said a good Samaritan followed the truck driver, cut him off and called 911.

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