Since 2012, around 300 Swedes have traveled to IS-dominated areas and about half of them have returned, although the number of returnees has declined in recent years. According to Karl Melin, Säpo is well acquainted with the Swedes who have joined IS, where they are and if they are on their way back to Sweden.

- We have a good picture. It allows us to immediately follow up returnees, he says.

Melin adds that for each person who returns, an individual assessment is made as to why they return and any tendency to commit crimes in Sweden.

- There are people who have completely distanced themselves from IS and people who are still radicalized, he says.

Säpo also monitors all returnees and suspicions of crime being investigated and forwarded to prosecutors.

Hard to prosecute

However, judging returnees for crimes committed in other countries is not always easy.

"It can be difficult to prove," says Melin.

However, according to the Minister of State responsible, Interior Minister Mikael Damberg, the conditions are good to get returnees legal.

- The government has significantly improved the terrorist laws in Sweden and several preliminary investigations into war crimes are ongoing, he says in a written comment to SVT.

The government must stop ducking

The opposition is of a different opinion. The moderates' political spokesperson, Johan Forssell, says that the Swedish terror legislation is far from sufficient to convict returnees for possible crimes. In addition, the penalty is too low and must be tightened according to him.

- The legislation is not in place. It is provocative that you can come back to Sweden without being held accountable, he says.

Forssell adds that the government now has to put the cards on the table on how to deal with the IS-Swedes - what should the legislation look like and where should they be legislated?

"It's high time the government stopped ducking and telling us what it wanted," he says.