“It is suspected that these men are important witnesses but there are no arrests,” Gavleborg police spokesman Michael Hedström told Swedish news agency, TT.
“We must also question a man who was injured in the altercation,” Hedström continued.
“We have 20 officers working on the case – there is a huge amount of work to get through to establish what exactly happened.”
Söderhamn is a town of around 11,000 in Gävleborg municipality, 250km north of Stockholm.