41 cases have been reported since the beginning of this year, compared to 20 in all of 2014.
"We have become better at asking, catching those stories and it's about asking the right follow-up questions so we can confirm suspicions better," says Magnus Bengtsson, asylum expert at the Swedish Migration Agency.
When the agency suspects that an asylum seeker has committed war or terror crimes, it refers the case to the Swedish Security Service Säpo for advice.
Most of the 41 cases reported this year are described by the migration agency as suspected terrorists or war criminals.
Bengtsson says these cases are usually difficult to detect.
"You have to remember that most of these people come here with a story, not a lot of documentation, sometimes no documents at all," he says.
People suspected of this type of crimes usually only get a temporary permit and are deported from Sweden as soon as possible.