A former U.S. Marine was released from a prison in Matamoros on Friday afternoon.
Jon Hammar has been held at CEDES prison since August, when he crossed a border bridge with a hunting rifle.
He was taken into custody and charged with carrying an illegal weapon.
According to his family, Hammar was told that he could bring the gun into Mexico if it was registered for and a fee was paid.
His defense lawyer said it was determined that there was no intent to commit a crime in this case.
Over the past five months, U.S. Senator Bill Nelson has been working with U.S. Customs and Border Protection, the State Department and Mexican authorities to get the 27-year-old out of prison.
During his time in prison, Hammar TMs family has been faced with death threats from other inmates.
U.S. Consolate officials escorted the former Marine safely back into the United States once he was released.
All of his charges have been dropped.