CHICAGO — Mayor Rahm Emanuel’s administration is scrambling to contain a furor over the city’s red-light camera system, which may have ticketed thousands of motorists under questionable circumstances.

Prompted by a Chicago Tribune investigation that revealed unexplained spikes in tickets issued, eight aldermen have asked the city’s top watchdog to launch a probe into the ticket surge and private attorneys are gathering information for a possible class-action lawsuit.

Emanuel has vowed to give motorists an extra chance to appeal tickets and to refund any issued improperly. More than 13,000 red-light tickets costing $100 each were generated at a dozen intersections where there were dramatic spikes in violations logged.

But critics say that simply writing refund checks won’t restore public trust the city’s system for enforcing violations.

“These spikes, you can tell they (the tickets) are fraudulent,” said Scott Waguespack, one of the aldermen who sent Chicago Inspector General Joseph Ferguson a letter asking for an investigation. “We are talking millions of dollars here and something is fundamentally wrong with the system.”