Columbia County detectives are investigating four overdose deaths in the span of six days, though preliminary evidence is pointing to a somewhat mundane explanation. “It’s very easy for people to attribute multiple overdoses to a ‘bad batch theory’ and I don’t necessarily buy that,” said Portage Police Department Detective Lt. Daniel Garrigan, of the four deaths between Aug. 30 and Sept. 5. The three victims, a 23-year-old Portage woman, 28-year-old Pardeeville woman, 48-year-old Lewiston woman, and 54-year-old Columbus man are not believed to have been connected or have been in similar social circles with the possible exception of one “associate” that is believed to be in common.