7:39 AM PT -- 1/19 -- Santos just addressed the accusation on Twitter, saying, "The reports that I would let a dog die is shocking & insane. My work in animal advocacy was the labor of love & hard work. Over the past 24hr I have received pictures of dogs I helped reduce throughout the years along with supportive messages. These distractions won’t stop me!"
Navy veteran Richard Osthoff choked up while claiming Rep. George Santos scammed him out of money intended to keep his dying service pooch alive ... he says the dog saved his life.
Osthoff recalled his alleged history with the freshman legislator from NY -- who's already fessed up to lying about his work experience and education -- in an interview with CNN, getting emotional as he told his story ... with his late dog's ashes in a box next to him.
The Navy vet says his pooch, Sapphire, saved his life when he was in a dark place after first getting out of the service ... and he's convinced he wouldn't be alive today without the dog.
Osthoff says Santos offered to help get the dog a life-saving medical procedure several years ago ... when Santos was going by his alias, Anthony Devolder ... but says he never saw a dime of the $3,000 Santos raised online.