A transit higher-up helped detectives arrest a well-known subway vandal, court documents state.

David Ortiz, 17, and other punks allegedly donned a mask and stole a side destination sign from a D train car at the Bay 50th Street station in Brooklyn about noon on August 16.

The teen also used a Philip screwdriver to steal a sign from a C train at the Van Siclen Avenue station on August 10-- and was spotted by a transit supervisor on a D train carrying the sign in a plastic bag, court papers show. The transit supervisor took a picture of Ortiz with a stolen sign in a plastic bag on the train.

The signs were valued by the MTA at more than $1000.

Authorities charged Ortiz with multiple counts of grand larceny, criminal possession of stolen property, and petit larceny, according to a Brooklyn District Attorney spokesman. He was released without bail being set.

Ortiz was known in the transit enthusiast community as part of a group of rail-obsessed kids that tried to conquer their subway with vandalism and other hijinks.

His social media pictures show him on the subway with teen Keyshawn Brown, who was arrested for causing an explosion on C train tracks in the spring in Brooklyn.