FBI agents were seen photographing vehicles at Cuellar's home in Laredo ...6,000 square feet, five bedrooms in a gated community — the wages of nine terms representing the residents of the Rio Grande Valley...
They also executed a separate search at office where Cueller's campaign is headquartered
Bureau would only confirm it is conducting an 'ongoing investigation'
Cuellar said in a statement that he will 'fully cooperate in any investigation'
The nature of the investigation remains a mystery closely guarded by the FBI
Cuellar is a Democrat who has harshly criticized Biden's border policies
He has also called VP Kamala Harris ineffective in her role as 'border czar'