Footage of a man indecently exposing himself in Raunds may have been circulated on social media.
Police are appealing for anyone who filmed the disturbing incident to contact them.
The man was in Marshall's Road between 1.45pm and 2.20pm on Thursday, June 27, when he exposed himself.
A video of the incident is believed to have been shared on Snapchat.
A police spokesman said: "The man is described as white, aged around 35, 5ft 7in, with blonde hair and of skinny build.
"Officers investigating the incident are appealing for anyone who witnessed it, particularly those who recorded it, to get in touch by calling 101, or Crimestoppers in confidence on 0800 555111."