In mid-1903 Tyner was investigated for corruption in the Post Office by special prosecutor Charles J. Bonaparte and Fourth Assistant Postmaster General Joseph L. Bristow. Tyner was indicted three times for fraud and one count bribery. Also indicted was First Assistant Postmaster Perry S. Heath. President Roosevelt stated the postal investigation revealed a condition of "gross corruption" in their offices. Allegations against Tyner and Heath ranged from gross negligence of office, criminal collusion, to actual participation in frauds, bribery, and financial profiteering. Tyner was acquitted for lack of evidence since Tyner's wife had removed his papers from his office in April. Bristow's investigation resulted in 41 indictments against 31 persons connected to the postal frauds. Four postal officers and employees resigned while thirteen workers were removed from office.