The man who claims to have found and returned Daniel Sturridge's stolen dog in 2019 is now suing the soccer star ... alleging the athlete has STILL not paid him the reward money he promised.
Foster Washington spelled it all out in a new lawsuit, obtained by TMZ Sports ... saying Sturridge owes him reward money -- which was reported to be around $37,000 -- for helping him get his Pomeranian, Lucci, back nearly 2 years ago.
THE BREAK-IN
Washington says after Sturridge claimed the dog had been stolen in a July 2019 burglary in Los Angeles .