“We went into an apartment and found the man. He was alone, unarmed and did not resist the arrest,” police spokesman Tomas Pärlklo told news agency TT.
Police authorities nationwide had been advised to look out for the suspect after a number of house searches in Karlskrona failed to reveal his whereabouts.
The murder is reported to have taken place shortly before lunchtime when the victim intervened to prevent a fight between his daughter and the 20-year-old.
The suspect is a Karlskrona resident with a history of violent crime.