Navy Vet Allegedly Scammed by George Santos Fires Back After Charges

The Navy veteran who claims Rep. George Santos cheated him out of cash intended for his dying dog's cancer treatment is happy to see Santos facing criminal charges ... he says George had it coming and karma's a bitch.

Richard Osthoff tells TMZ ... Santos deserves to spend time behind bars and he hopes the judge throws the book at him.

The vet says he's not the only one glad the feds busted Santos, running off a list of groups he claims have been wronged by George. While he's surprised at the timeline, Richard says he's glad Santos finally has to face the music ... and he believes more charges could be coming.

As we reported ... the FBI arrested Santos Wednesday for a variety of alleged misdeeds, including lying. He was charged with 13 counts of wire fraud, money laundering, theft of public funds and making false statements to the House of Representatives.

For his part, Santos insists he's innocent, calling the indictment against him a "witch hunt" and refusing to resign.

Osthoff, you might recall, claims Santos created a GoFundMe campaign to pay for a lifesaving surgery for his cancer-stricken dog Sapphire ... only to see Santos make off with thousands of dollars in donations, leaving Sapphire for dead.