Last year, the General Motors engineer who quietly signed off on a fix to an ignition problem that has resulted in at least 13 deaths claimed in a deposition that he had no knowledge of making this incredibly important improvement. But after Congressional investigators have turned up all sorts of evidence showing that he did indeed give the okay for this fix, the engineer reportedly says he simply forgot about it.

He is one of two engineers suspended in April for their part in allegedly trying to sweep this defect under the rug while more than a dozen people died.

The NY Times reports that Congressional investigators recently put him through a 10-hour round of questioning over his involvement.

To recap for those not entirely familiar with the case — In 2001, before any of the defective cars hit the road, GM noticed the possibility that the ignition switches in certain new vehicles could be easily turned off if the key in the ignition is attached to a heavy keychain, or gets bumped by the driver. This causes the engine to quit, and results in a loss of power steering and brakes. Most importantly, the car’s airbags become useless.

As owners and dealers complained about the problem, GM mulled over various fixes to the problem but did not act. Meanwhile, accidents were happening and people began to die. Then in 2006, the engineer in charge of these ignitions gave the go-ahead to the third-party manufacturer of the switch to start producing a new version that would not turn off so easily.

However, the part number was never changed to reflect this fix, so new switches commingled with old, defective ones in dealerships’ inventories. When GM finally got around to issuing the recall in 2014, it not only had to recall all the vehicles made before the ignition switch was fixed, but it had to subsequently add on another million vehicles made after that upgrade because some of those newer cars might have the old switches in them.

Signing off on a change to an ignition switch is no small thing, and the failure to change the part number after this fix gives a stink of cover-up to the engineer’s actions. But in a 2013 deposition for a lawsuit brought against GM by the parents of a woman who died while driving a Chevy Cobalt, the engineer stated, “I don’t ever recall authorizing such a change.”

Then on May 19, while being grilled by Congressional investigators, the engineer admitted he did indeed make the change, but that it must have just slipped his mind because it had been seven years and the ignition fix was not the only change he was making at the time.

The family involved in that lawsuit has asked the court to reopen its case against GM, claiming the engineer perjured himself by saying that any changes made to the ignition switch happened without his knowledge or say-so.

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