Police are searching a canal path following reports of a man approaching women and making sexual propositions.
Gloucestershire Police said the first reported case happened at about 13:15 BST, close to Severn Vale Drive in Quedgeley.
The man approached a lone woman walking her dog and handed her note asking her to expose herself.
He then approached four other women and acted in the same manner, the force said.
Officers are urging anybody who sees the man not to approach him, but to call 999.
He was described as a black man in his 30s, who measures about 5ft 6in (1.7m) tall, and was wearing a black hooded top and black jogging bottoms.
His mouth was covered with a balaclava and he was wearing glasses and carrying a notebook that he showed to the women he approached.
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