Dave Mirra -- Possible CTE ... Officials Say

BMX legend Dave Mirra may have suffered from CTE -- just like several ex-NFL players -- and it may have been a factor in his suicide ... so says the Mayor of Greenville, NC.

Mayor Allen Thomas says officials are still gathering the facts surrounding Mirra's death -- but says he fears he may have had CTE from head trauma he suffered during his extreme sports days.

Thomas even invoked the name of ex-NFL star Junior Seau -- who took his own life in 2012 ... and was later found to have the brain condition.

Police chief Mark Holtzman says investigators have spoken with a group of Mirra's friends -- who Mirra was with minutes before the suicide -- and they said Dave didn't appear suicidal.

However, he had been showing signs of depression in the past, Holtzman says.

As we previously reported, Mirra's body was discovered in his truck Thursday and cops say it's clear he took his own life with his own gun.