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 refund any fines issued improperly for 13,000 red-light tickets generated at a dozen intersections where there were dramatic spikes in the number of tickets. He said he will offer motorists an extra chance to appeal the $100 fines.

But critics say simply writing refund checks won’t restore public trust in 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.”