NEW YORK (PIX11) — Police are investigating a string of recent sex crimes in the MTA’s transit systems, and all involved either forcible touching or sexual abuse, officials said.

The five recent incidents are unrelated, but some involve teenagers, officials said.

Police said around 5:30 p.m. on June 2, a 28-year-old woman was walking on a subway station stairway in Tribeca when an unknown man placed his hand up her skirt and touched her in a sexual manner. The suspect ran off after the incident. The woman was not injured, police said.

On Monday, police said a 15-year-old girl was on an MTA bus in Staten Island when an unknown man rubbed his hand between the girl’s legs over her clothing. Police released a video of the suspect.

A few weeks ago inside the 59th Street and Fourth Avenue station, police said a 17-year-old boy was standing on a southbound R line platform when an unknown man approached him and asked, “How big?”

Police said the man then pointed at the victim’s groin area and grabbed him in a sexual manner over his clothing. When the train arrived, the victim got on. He was not physically injured.

On May 25, police said a 16-year-old girl was aboard a northbound No. 5 train as it was entering the Gun Hill Road station in the Bronx when an unknown man grabbed her buttocks, police said. The man then got off the train and ran.

On Sunday, a 26-year-old woman was leaving the Grand Avenue-Newtown subway station in Queens when an unknown male grabbed her buttocks, police said.

Submit tips to police by calling Crime Stoppers at 1-800-577-TIPS (8477), visiting crimestoppers.nypdonline.org, downloading the NYPD Crime Stoppers mobile app, or texting 274637 (CRIMES) then entering TIP577. Spanish-speaking callers are asked to dial 1-888-57-PISTA (74782).