Drones are scouring the banks of Poland's River Vistula just south of Warsaw for a 5m Indian python authorities have warned could be hungry and aggressive.
Police from the town of Piaseczno, which lies close to the Polish capital, have asked people to stay away from the river until the renegade reptile is recovered.
The four drones, part of a search team comprising four boats and up to 80 volunteers, police officers and firefighters, have taken over 2000 photographs now being studied by wildlife experts in the hope they can spot the snake lurking in the wooded banks of Poland's longest river.
Native to India, Sri Lanka and the East Indies, Indian pythons can reach 6m long and can swallow a deer whole. Although there are no reports of them eating people. Adam Hryniewicz, a zoologist at Warsaw Zoo, said that, if scared, they can bite and could even break limbs by coiling themselves around their victim.
So far no trace of the snake has been found other than a huge shed skin recovered over a week ago, which triggered the hunt when it was found nine days ago.
Radoslaw Ratajszczak, a zoo director, told the TVN television network that the python's natural camouflage makes it hard to spot, and that cool weather now covering Poland will make the animal inactive and so even harder to find.
He also suggested the authorities might have to widen the search.
"It's a great swimmer. If it went into the Vistula and swam with the current it could be a 100 kilometres away," said Ratajszczak, although he added the snake could also have succumbed to the cool weather.
Just how the python got into the river remains unclear, but reptile experts believe that it may have been kept as an exotic pet but then released into the wild when it became too large for its owner to handle.
Piaseczno officials have opened a criminal investigation on the grounds that the snake's release has endangered public safety.