A pair of good Samaritans, including an 82-year-old man, were thrown into a Central Park lake on Monday when they tried to stop a thief from stealing an elderly woman’s backpack, cops said.

The two victims had seen a thief taking the 72-year-old woman’s backpack from a bench at Lenox Avenue and Central Park North around 9:15 a.m. and attempted to snatch it back, police said. 

The crook then pushed the man, 82, and female good Samaritan, 44, into the Harlem Meer during the struggle, cops said.

The elderly man suffered a cut to his head, and the woman was injured on her left arm while trying to help him. Both of them were taken to St. Luke’s Hospital for treatment and listed in stable condition.

Connecticut resident Justin Bonhomme, 25, was arrested and charged with assault and petit larceny, cops said.