Four Swedish citizens, one a Tunisian with Swedish residence, sentenced for preparing a terrorist act in 2010, will be released Saturday.

They planned to “kill as many as possible” in a planned bloodbath against the headquarters of the Danish newspaper Jyllands-Posten over Muhammad cartoons.

The convicts have only served two-thirds of their punishment, common for the Scandinavian penitentiary system. Since their sentencing they’ve been moved to different institutions throughout Sweden.

The Swedish Prison and Probation Service report that all of the terrorists had been reported for threats of violence to staff and other prisoners during their prison sentence, with one requiring isolation after attempting to radicalise fellow inmates. Apparently these incidents weren’t sufficient enough reason to postpone their release.

A senior researcher from the National Defence College and a leading expert on terrorism, Magnus Ranstorp tells newspaper Dagens Nyheter:

“It is not possible to say with certainty that they will absolutely relapse and become dangerous upon release. But in such crimes there is a great risk of relapse” as they are treated as ‘rock stars’ in their previous environment upon release.”

It has been revealed that all four Islamists living in Sweden and currently aged 37 to 52, were approved for post-release monitoring from Sweden’s Security Service (SÄPO), if they so choose. Two of the terrorists are considered a high risk of relapse according the the Prison and Probation Service.

Ranstorp further asserts that with 1,500 terrorists up for release in 2019, the lack of rehabilitation programmes to re-socialise and re-integrate it is a topic neglected internationally.

However, he does acknowledge that some countries are beginning discussions on compulsory programmes as prerequisite for conditional release. Germany and Denmark have talks during the convicts time in prison.