A man pushed a member of staff and caused damage after becoming abusive when last orders were called at a Brackley pub, according to police.
Police officers are appealing for witnesses following the incident in Lark Rise on Tuesday (September 25).
Between 11pm and 11.30pm, a member of staff asked all customers to finish their drinks as the pub was closing.
A police spokesman said: “A man then became abusive, leaving the pub but returning a short time later to bang on the windows.
“He then re-entered the premises and pushed a member of staff before smashing a window and damaging a sign at the front of the pub.
“The offender is described as a white man, 30-40 years old, about 6ft, of stocky build with short brown hair and a short dark beard.
“He was wearing a dark blue knitted jumper and dark denim jeans.”
Anyone with information should contact Northamptonshire Police on 101. Alternatively, call Crimestoppers anonymously on 0800 555111.