Hooters police Village of Oak Lawn has launched an internal investigation of an off-duty police officer accused of attacking a grandmother over a disputed bill at a Hooters restaurant.The probe comes after a civil suit was filed Wednesday and after the coming forth of several witnesses who tell NBC Chicago that other responding officers protected their brother in blue.”If something happens with any employee, yes, the mayor wants to know. All of us want to know, so our job now is before we point any fingers is to sit down and figure out what exactly happened several months ago,” Oak Lawn Mayor David Heilmann said Thursday.A security camera inside the Oak Lawn restaurant captured the Jan. 10 incident. In it, 54-year-old paralegal Livier Torres can be seen approaching the counter to dispute a charge on her bill. Also seen are the restaurant’s manager and the off-duty Oak Lawn police officer Joseph Schmidt. After discussing the matter for several minutes, Torres ultimately puts her credit card down still seems incensed. Then, according to Torres’ daughter, Schmidt made a remark that dramatically changes the dynamic. “He was telling her, ‘All you people are the same,’ and I didn’t understand what he meant by that,” she explained. “She was like, ‘What do you mean all the people are the same? Are you saying a prejudice remark because I’m Mexican?’”Just as the manager returns to have Torres sign the credit card receipt, Schmidt swings his arm around Torres’ neck and at one point …