PO3 Edison Namocatcat said the robbers entered the Mercury Drug outlet on Narra Avenue by destroying its back door and in matter of minutes, carted away goods and the stores earnings for two days.
Namocatcat wondered why the people outside the store did not alert the police when its alarm system sounded at the height of the robbery.
The robbers gagged the stores security guard and took his service firearm, a shotgun.
Policemen reportedly patrolled the vicinity of the drug store at about 11 p.m. and left after a few minutes to continue their rounds.
The police consider the robbery the biggest so far in Agusan del Sur.
Caraga residents have expressed concern over increasing criminality in the region, noting a rise in robberies and akyat-bahay (house burglary) incidents.