The probe will try to establish the exact circumstances of the tragedy, focusing on possible manslaughter, Polish state news agency PAP reported.
Tragedy in Jantar
The deceased was one of four bystanders who attempted to comb the sea near the Jantar beach for a person who was reportedly drowning.
Amid high waves, the four people themselves began to drown, police said. Two of them managed to return ashore, but the other two had to be rescued from the water and resuscitated.
The 32-year-old man was taken by helicopter to a hospital, where he subsequently died on Wednesday night.
The other man, 36, remained hospitalised "in a serious condition," reporters were told.
Police said someone may have misled the four beachgoers by falsely claiming that a person needed help in the water, the PAP news agency reported.
Drowning toll rises
Meanwhile, the government said on Friday that one person drowned in Poland the previous day, bringing the drowning death toll since April 1 to 176.
The authorities continued to advise beachgoers to use caution when swimming and to follow the instructions of the lifeguards.
(pm/gs)
Source: PAP, dziennikelblaski.pl