They say the incident happened outside Stratford upon Avon School, in Alcester Road, at around 9.30am today, Thursday.
A spokesman said: “We are appealing for information, dashcam or other video footage.
“If anyone has seen a man acting suspiciously around the school this morning, or over the past week, please contact Warwickshire Police.
“There will be increased patrols while investigations continue.”
Call 101 quoting incident 75 of 28 April 2022.