The gunmen arrived at the estate of Deogracias Pinzon Suarez, former mayor of Enciso, shot him in the head and then escaped, according to Santander Police commander Edgar Nieto.
Also on Sunday, in a nearby municipality, university student Lina Dominguez Estupinan was shot dead.
According to reports, Estupinan was found half-naked in a forested area. She had been missing for several days before her body was discovered. Authorities are investigating whether sexual abuse was involved.
Police have confirmed that the two events were unrelated.