( CNN ) -- An Oklahoma City police officer is accused of sexually assaulting several women while on the job , his department said . The case started after one woman came forward and accused Officer Daniel Holtzclaw of `` sexual impropriety '' during a traffic stop , Oklahoma City police Capt . Dexter Nelson told CNN . Holtzclaw , 27 , was arrested Thursday and faces nine charges , including three counts of forcible oral sodomy , two counts of indecent exposure , two counts of rape and two counts of sexual battery , according to the Oklahoma County Sheriff 's Office . After the first woman 's complaint , investigators started looking into all of Holtzclaw 's traffic stops for other potential victims , CNN affiliate KOKH said . Nelson said authorities found six other victims . He said some of the women `` were initially less than cooperative , but investigators were able to gain statements , '' he said . Officials said all the alleged attacks took place during traffic stops , CNN affiliate KFOR reported . The city 's police chief said there may be more . `` We kind of anticipate there may be more victims out there because this goes back to February -- February was the earliest that we have here , through June , '' Oklahoma City Police Chief Bill Citty told reporters . `` If there 's anyone that was victimized by this officer , we certainly want to hear from them . '' It was not immediately clear whether Holtzclaw had an attorney . His bond is set at $ 5 million . CNN 's Darrell Calhoun contributed to this report .
An Oklahoma police officer is accused of attacking women while on the job . The alleged assaults took place over several months , authorities say . Police chief : `` We kind of anticipate there may be more victims out there ''