CONCOURSE, the Bronx (PIX11) — Police are asking for the public’s help finding the knife-wielding assailant who sexually abused an 11-year-old girl aboard a subway train rolling through the Concourse section of the Bronx.

The victim was aboard a northbound No. 4 train approaching the 149th Street – Grand Concourse around 3:25 p.m. Oct. 18 when the man approached her, according to authorities. He showed her a knife, told her in Spanish to be quiet, then felt her leg, waist, and buttocks, officials said.

The assailant left the train at the 161st Street – Yankee Stadium stop, police said. The victim was not physically injured during the ordeal, authorities said.

Investigators released a sketch of the suspect late Wednesday, appealing for tips from the public to help track him down. The sketch shows him as bald, and he’s described as about 40-years-old and 5-feet tall.

Anyone with information in regard to this incident is asked to call the NYPD’s Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). The public can also submit their tips by logging onto the CrimeStoppers website at https://crimestoppers.nypdonline.org/ or on Twitter @NYPDTips.