A creep who exposed himself on the subway and masturbated in front of a female straphanger in Brooklyn this week was still on the loose, cops said Saturday.

The NYPD released a photo of the man they say was behind the lewd act, which happened on a southbound 3-train approaching the Franklin Avenue station in Crown Heights at about 6:30 p.m. on Thursday.

The victim was a 37-year-old woman, police said.

Anyone with information can submit tips by calling 800-577-TIPS, through the CrimeStoppers website at at https://crimestoppers.nypdonline.org/ or on Twitter @NYPDTips.