The Boscombe Sovereign Shopping Centre was evacuated yesterday after a man was stabbed.
A man in his 40s was arrested by officers after an incident in the 99p store at around 1pm.
The victim was taken to Bournemouth Hospital with non-life-threatening injuries.
DI Joe Williams of Dorset Police said: “We are appealing to anyone who may have witnessed this incident, which we believe may have happened in the area of the 99p store within the Sovereign Centre to contact us.
“We would like to reassure members of the public that there is not any further risk to their safety as a result of this incident.”
Witnesses and anyone with information should call 110, quoting incident number 8:171.