The incident happened at an open-air military event near the north-central city of Ciechanów on Sunday, Polish state news agency PAP reported.
A police Black Hawk helicopter damaged a high-voltage power line while taking off, according to officials.
Poland's National Police Headquarters said on Monday it was investigating the incident and “all the collected evidence will be forwarded to the prosecution office as soon as possible.”
It added that the State Commission on Aircraft Accidents Investigation (PKBWL) had also been notified.
Meanwhile, Piotr Tyszka from the Regional Prosecutor's Office in Ciechanów said that the investigation would focus on the possibility that the incident "posed the risk of an air disaster.”
The incident took place at a military picnic to mark 103 years since the Battle of Sarnowa Góra during the 1920 Polish-Soviet War, the PAP news agency reported.
(pm/gs)
Source: PAP, Polsat News