Police are appealing for information after a dog walker reported seeing a naked man in Worden Park in Leyland.
The incident happened at about 4.15pm on Wednesday, July 2, when a 32-year-old woman out walking her dog saw a naked man running on the opposite side of the river.
When he saw the woman the man ran into some bushes and emerged fully clothed before making off.
He was described as white and wearing a blue or grey T-shirt and red shorts.
Police are appealing for any witnesses to contact them on 101 quoting log number 1089 of July 2.