Parents and children at a swimming pool and play area in Topsham were shocked to see a man who stripping naked and exposed himself.
Nicholas Courtenay flashed at children and passers-by during the half term holiday in June last year and went on to sexually assault two women two days later.
He also kicked out at an officer who detained him and spat inside and outside a police car.
Courtenay is currently being treated at a mental hospital and a fact-finding trial was held in his absence at Exeter Crown Court because he has been ruled as unfit to plead.
Judge David Evans told a jury that their task was to decide whether Courtenay did the alleged acts, rather than come to a conventional verdict of guilty or not guilty.
They decided he had committed the offences and the Judge adjourned sentence to await further psychiatric reports.
The only allowable sentences in this type of trial are a hospital order or an order that the defendant be treated in the community.
Courtenay, aged 42, of no fixed address, Exeter, was accused of two counts of exposure, two of sexual assault, two of criminal damage, two of common assault, and one of assaulting an emergency worker.
The jury at Exeter Crown Court ruled that he had done all the acts alleged and the Judge adjourned the case for psychiatric reports.
He suggested that Courtney should be transferred from Exeter Prison to Langdon Hospital in Dawlish for further neurological assessment as soon as possible.
Miss Kelly Scrivener, prosecuting, said a group of children and adults were queueing to get into Topsham Swimming Pool at noon on Friday, June 4, when Courtenay walked past them and into the pool.
The first adult to follow him into the male changing room saw him exposing himself and urinating on the floor, even though there was a urinal just five feet away.
He turned away to prevent a child seeing Courtenay, who pulled up his trousers and fled into the pool when challenged by a second adult.
He waded, fully clothed, towards a group of mothers and children and a lifeguard was so alarmed that he jumped into the pool to stop him and throw him out.
Courtenay was seen discarding his wet clothes as he walked down a path leading to a small play area next to the back tennis court in Topsham, where there were parents and children.
He pushed an empty swing as the parents ushered away their children and the police found him still naked in a nearby garage. He spat at their police car as he was being taken into custody.
He was released and returned to Topsham at around 5.30pm on Sunday, June 6, sexually assaulting a woman in Countess Wear on the way. He grabbed her bottom as she stood near a shop.
He then moved on to the university sports field, where he terrified a 17-year-old girl by jumping out of the bushes at her and threatening her with a scooter which her younger brother had been riding.
Courtenay sexually assaulted a young mother at the same location shortly afterwards by grabbing her breasts before he attacked a passer-by outside Plants Galore by slapping his arm.
He kicked out an one of the police who had been called to the earlier incidents and who arrested him in Topsham Road.
Courtenay has a history of bizarre offending and in 2014 he stripped off and climbed onto the altar at Exeter Cathedral before assaulting a pensioner on his way out.
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