The Swedish criminal proceedings are structured, partly based on a preliminary investigation and partly based on a main hearing. The preliminary investigation aims to investigate whether a crime has been committed, and who may be held responsible for the crime. The main hearing aims to determine, in a legally secure manner, whether the suspect can be held responsible for the crime.  During the investigation, the suspect can be detained, if there is a risk that the suspect will interfere with the investigation. The suspect can also be subjected to restrictions, which means that they can’t contact other people outside the detention facility. Furthermore, the restrictions can keep the suspect from meeting other detained individuals, resulting in total isolation and mental health issues. The purpose of the restrictions is to prevent the suspect from harming the investigation by contacting other people or fellow suspects. The necessity of restrictions is related to the procedural principles in court. The principles entail that witnesses generally must be heard in court, regardless of whether they have been heard by the prosecutor or police during the preliminary investigation. The reason is to provide the court with the best possible conditions to conduct a thorough assessment of the evidence. Therefore, the preliminary investigation becomes particularly vulnerable regarding witness testimony since the suspect may influence the witnesses by threats or violence. The division in the criminal proceedings, between the preliminary investigation and the main hearing, promotes the use of detentions and restrictions, particularly in cases of more severe criminality. The division can be described as a conflict between the interests of efficiency and legal security. The interest in efficiency is expressed through the preliminary investigation and the judicial system’s ability to resort to coercive measures. This ensures that the legal system can investigate and prosecute crimes. The interest in legal security is expressed through the main hearing and the procedural principles in court. This ensures that no one is wrongfully convicted. The purpose of this study is to investigate which application problems that may occur when the judicial system applies the restriction legislation. Is there room for a different interpretation of the law? Can the law be applied differently based on the purposes of the law? If the law can’t be applied differently, what revisions are necessary to align it with its intended purposes?