Documents released by the National Transportation Safety Board on Thursday related to the July derailment of a Metro Silver Line Metro train show Metro officials were aware of potentially dangerous deteriorating rail ties near East Falls Church for more than a year before the incident.

In addition, transcripts of interviews between Metro management and track inspectors suggests investigators believe inspectors may have been fabricating inspection reports by copying the exact same measurements from month-to-month.

“So how did your measurements stay the same if your ties are getting worse and worse?” asked Metro safety officer Robert Davis, interviewing an inspector in early August who had been overseeing the crossover near East Falls Church. “After three years how did the measurements all be exactly the same?”

“You’re not going to tell me that the track didn’t move a sixteenth of an inch or an eighth of an inch or a quarter of a inch over that time,” Davis added. “I can go out here and gauge this track out here and I could find different gauge everywhere right now.”

“If I believed you for one second… I would end this right now and move on, but you know as well as I do that you can’t look me in the eye and tell me that, because you’re an honest man.”

Metro announced in August that it was launching a criminal investigation into the derailment, but no charges have been filed.

Days after the July 29 derailment, the NTSB indicated that Metro inspectors may have been aware of problems with the tracks in that spot for years before the derailment. Because of the decayed state of the wooden rail ties, the running rails had not been properly secured in place, and the tracks had spread so wide that the Silver Line train fell of its mooring.

But the inspection reports released this week by the NTSB show much more explicitly just how much Metro knew in advance of the derailment: Every report from January 2015 to June 2016 listed 15 deteriorating rail ties in that area, and yet the problem remained unaddressed.

In a summary of the NTSB investigation sent to the region’s lawmakers Thursday, the regulatory agency said that the derailment occurred as a result of “Washington Metropolitan Area Transit Authority’s ineffective inspection and maintenance practices and inadequate safety oversight.”

This is a developing story. Stay tuned for more.