The FBI is involved in the Department of Justice’s criminal investigation into the certification of the Boeing 737 MAX, according to a Wednesday Seattle Times report.

The FBI’s Seattle field office is close to the 737 plant and the Federal Aviation Administration offices, where officials partook in the certification process for the planes, two of which crashed in recent months.

Criminal investigations into the aviation industry are exceedingly rare in America and point to the seriousness of the fatal and well-publicized accidents.