Jane Beall, 23, said she was using a public bathroom at Burleigh Heads, Queenland, on Tuesday when she noticed a phone being slipped under the wall between her stall and the one next to her.
"I quickly left and told my friend who was waiting outside," Beall said in a Facebook post. "I went back in again and decided to film - in the hopes to have evidence and prove to myself I wasn't being paranoid."
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Bella then went inside of the stall, pressed record, and caught the phone poking in seconds later.
Once the man saw Bella's phone, he pulled back.
That's when Bella called police; while she was on the phone with officers, the man fled the bathroom and started sprinting away.
Not letting him get away that easily, Bella and a friend followed the man while police were on the line.
The suspect was described as a 40-year-old white man with a crew cut and gut.
Police have yet to comment on an arrest but Beall said the whole experience had her sick to her stomach.
"Please be careful and aware of your surroundings - even if you think you're in the privacy of a toilet! It was by chance I saw him the first time and caught him on film the second time!"
Storyful contributed to this post