The man was one of two men from the Örebro region in central Sweden arrested on Tuesday in connection with Operation Viking, a coordinated effort by police in four Scandinavian countries to combat the spread of child pornography.
Following the man's suicide, Swedish police filed a complaint against themselves, reports Sveriges Television (SVT).
The man was one of approximately 80 people in Sweden, Finland, Norway, and Denmark who were taken in for questioning or arrested on suspicions of having child pornography on their computers.
The man was released by police following his interrogation.
He then went home, wrote a farewell letter, and killed himself.
“Our initial analysis is that we didn't break with procedure,” said Örebro police spokesperson Torbjörn Carlson to SVT.
Several of the roughly 20 men targeted by Swedish police were later taken to psychiatric clinics for observation, according to SVT.
“We had no legal reason to hold him and there were no signs that he needed care or help,” said Carlson.