The victim, Castor Gamalo, 39, was shot in the back with a caliber .45 pistol, said Chief Superintendent Dionisio Coloma, regional police director.
Gamalo, whom doctors have declared out of danger, had just come from his classes at the Eastern Visayas State University (EVSU) when he was fired at in the citys Quarry district, about 100 meters away, past 6 p.m.
Gamalo, also the regional chairman of the Alliance of Concerned Teachers-Eastern Visayas, has been teaching social science subjects at the state university for 15 years now.
Coloma said probers were looking into his being the regional coordinator of the Partido ng Manggagawa as well as the president of the EVSU Faculty and Employee Association as possible angles in the slay attempt.
Gamalo, who used to be a regional coordinator of the Freedom from Debt Coalition, has led recent protest rallies against EVSU president Bonifacio Villanueva.
In previous statements, Villanueva had denied the allegations of Gamalos group that he was involved in irregularities.
Last May 12, Rev. Edison Lapuz, of the United Churches of Christ in the Philippines and regional chairman of the Katungod-Sinirangan Bisayas, was gunned down in front of his house in San Isidro, Leyte.
Militant groups in the region have blamed the military for the attacks on activists.
But Maj. Gen. Jovito Palparan, commanding officer of the Armys 8th Infantry Division based in Catbalogan, Samar, has denied the accusations.