A watchdog group is calling out General Motors for under reporting the number of deaths connected to faulty ignition systems.

The Center for Auto Safety say that over 300 people have died in GM cars where the airbags did not deploy compared to the 12 that GM reported to federal investigators.

“Without rigorous analysis, it is pure speculation to attempt to draw any meaningful conclusions,” the company said in a statement refuting the group’s claim. “In contrast, research is underway at GM and the investigation of the ignition switch recall and the impact of the defective switch is ongoing.”

Still, the company has hired outside investigators to look into the recall.

The Center for Auto Safety is taking the National Highway Transportation Safety Administration to task, saying they were negligent in following up on reports of accidents attributed to the GM system.

“The only way NHTSA could not see a defect trend is if it closed its eyes,” said the group in a letter to the NHTSA.