Yet another gal pal of the man suspected of gunning down his corrections officer ex-girlfriend earlier this month has come out of the woodwork — for allegedly helping the accused murderer torch a third lover’s car.

Shirley Mejia allegedly helped purported killer Keon Richmond set fire to an unnamed ex’s vehicle on Oct. 23, according to court papers.

Mejia was indicted on third-degree arson charges Wednesday before Brooklyn Supreme Court Justice Bruce Balter, at which time defense attorney Douglas Appel entered a not guilty plea on her behalf.

Richmond was also named on the indictment, but was not in court.

It remains unclear what accelerant the lovebirds used in the East New York fire, sources said.

The 24-year-old appeared bored in court Wednesday, shifting back and forth and playing with her nails as the jurist, Appel, and ADA Joanna Lettieri discussed the case at the bench.

Mejia was eventually released without bail and declined comment as she scuttled to the elevators.

Richmond, 32, is the main suspect in the fatal shooting of rookie Corrections Officer Alastasia Bryan — who was hit five times as she sat in her car in the Flatlands on Dec. 4.

The homely ladies man was found by cops hiding in a closet 10 days later.

A high-ranking member of the Pay Back Crips street gang whose rap sheet boasts 30 prior arrests, Richmond is suspected of shooting Bryan, 25, because she had him collared for stealing her car, sources previously told The Post.

He has yet to be charged in that crime.