As the above video shows, police say a 35-year-old woman was walking on Morgan Avenue in the East Williamsburg section around 8:10 p.m. when she noticed that a man was following her.
She stopped to let the man go past and then kept walking.
But he got behind her again when she turned onto Stagg Street.
That's where, police say, he ran up to her from behind, jumped on her back, wrapped his arms around her neck, and took her to the ground before forcibly touching her underneath her clothes and running off.
The victim was shaken but declined medical attention.
NYPD Special Victims Unit detectives are investigating.
Police are asking people to watch the video in hopes someone recognizes the man and calls them.
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).
Tips can also be submitted onto the Crime Stoppers website or on Twitter @NYPDTips.
MORE NEWS: Trump Organization, CFO Allen Weisselberg plead not guilty to tax fraud charges
* More Brooklyn news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube
Submit a News Tip