Krantz was murdered last September in Gothenburg. She was attacked by a man late at night who then attempted to rape her and eventually beat her to death.
In its judgement, the court in Gothenburg said there was little doubt the man had murdered Krantz.
"I am happy that he was judged fro this crime because we are certain that we have the right person," district prosecutor Stina Lundqvist tells Swedish Radio News.
The man's attorney says he will appeal the decision and says his client is innocent.