Authorities in southeastern Finland have ended their search for a suspected fourth downed drone, after the investigation revealed the source of the suspicious activity was a local resident burning rubbish.
Authorities were alerted on Wednesday to a black plume of smoke in an area close to where a previous UAV was discovered earlier this week.
Police Superintendent Jukka Tylli confirmed to Yle that the search began in an area north of Rautalahti after a tip was received from a member of the public.
"We believe that the tip is reliable enough to warrant a search," Tylli said at the time.
However, after imposing a no-fly zone in the area to aid the search, police traced the source of the smoke plume to a smouldering rubbish heap.
"Now we are investigating whether this person is guilty of an environmental crime," Tylli said on Thursday.
On Wednesday, the Border Guard confirmed that authorities had destroyed a third drone that was found on lake ice in Parikkala.
Members of the Southeast Finland Border Guard had also joined the police in the search.
Up to 2,500 drones
According to the Finnish Defence Forces (FDF), Ukraine has launched up to 2,500 attack drones at Russian targets near Finland.
In an aim to put a dent in Russia's ability to finance its war, Ukraine recently started attacking Russian oil ports around the Gulf of Finland.
According to the FDF, Russia's air defences have been on high alert due to Ukraine's strategy. Russia has repeatedly closed down the airspace over St Petersburg to civilian traffic.
PM takes territorial violations seriously
Finnish Prime Minister Petteri Orpo (NCP) meanwhile said on Wednesday afternoon that Finland takes violation of its territorial integrity very seriously. He said that Finland has sent such a message to Ukraine.
Orpo told Yle that amid Russia's continued brutal attacks, Ukraine has the right to defend itself.
The PM also noted that Finland has been building up its drone defence capabilities for years, but that no country has the capability to protect itself from such incidents 100 percent of the time.
Article updated at 13:36 on Thursday 2.4.2026 to reflect that the smoke plume originated from a burning rubbish heap.