A Pittsfield city councilor has been indicted by a grand jury on a charge of buying illegal prescription painkillers and tipping off a dealer concerning a pending drug bust. Paul Capitanio was indicted Monday on drug conspiracy and accessory charges. State Police allege that the 57-year-old Capitanio was buying oxycodone pills from a dealer in August when he gave him information about an upcoming raid. Police say the dealer was caught on tape during a wiretap investigation telling a major dealer that a ‘‘councilman friend’’ had tipped him off about upcoming drug raids. The dealer allegedly later told police that he was referring to Capitanio. Capitanio’s attorney, Timothy Shugrue, told The Berkshire Eagle that his client denies the allegations and is not an addict.