Complex sentence: During the custodial time of 5-6 month did even further die and finally was a man who the Swedes believed to be some kind of leader rebel, become publicly executed at the square "Stortorget" in Malmö.
Split into simpler sentences: During the custodial time of 5-6 month did even further die. Finally, a man, who the Swedish authorities believed to be some kind of rebel leader, was publicly executed at the square "Stortorget" in Malmö.