Stefan Lindblad, who owns Swedish construction firm Llentab Group, doctored a cylindrical bird box to make it look like the speed cameras used in Sweden, which are usually long and thin with curved edges.
The CEO first put up the fake camera a year ago after becoming fed up with Swedish drivers racing past his office in Kungshamn, on Sweden's west coast.
He took it down after his efforts caused a stir after being reported in regional newspaper Bohusläningen, but has since returned it to the roadside this summer, causing people in the area to get in a flap again.
A spokesperson for Uddevalla police, which is looking into the incident, told The Local on Wednesday that officers were investigating whether or not Lindblad had sought permission to put up the box.
Under Swedish law, erecting objects in public areas, such as by a roadside, is illegal.
"If it's placed in a municipal area like this one, you need permission from police first," said Stefan Lång.
"If there's no permission, it needs to be taken down."
Lång said he had not driven past the fake camera himself but believed it looked convincing.
“I’ve only seen photos of it but I see why it could be easily mixed up with a real speed camera when you see it from a relatively far distance.”
He said he understood that feathered residents were still able to use Lindblad's box to nest in, adding "at least he’s being nice to the birds”.
The Local has been unable to reach Stefan Lindblad for comment, but the businessman made his thoughts very clear when he was contacted by a journalist at Bohusläningen earlier this week.
"I put it up last year and I think it worked well until you on Bohusläningen wrote about it. It destroyed all my good intentions," he told the paper, refusing to confirm whether or not he had sought authorization for the box.
According to Swedish Transport Agency figures reported in Bohusläningen, most people in the area have stuck to the speed limit of 50km/h in recent years, with an average road speed of 49km/h recorded in 2013.
"It is clear that you can not set up your own devices in the road area without permission," said Lennart Hellsing, a press spokesman for the agency.
"We take down many illegal signs, for instance for flea markets, and this is the same thing. Things that are set up in the road area must have a permit," he said.