Houston we have a problem.  America's Got Talent has a controversy on their hands. On Monday night, a stuttering country singer named Timothy Michael Poe claimed he was injured in grenade blast while serving in the National Guard in Afghanistan -- and then wowed the Texas crowd and judges with his crooning.

But yesterday, a person in the know said the show's producers didn't check out his story to see if it was legit and a Minnesota Army National Guard spokesman says no records exist that show Poe was involved in such an incident.

Poe, however, told TMZ his injuries and his stutter are real and he plans to sue his ex-wife and others for saying he's a fraud.