SKOPJE, North Macedonia (AP) — North Macedonia authorities said Saturday that four prison officers, including a police commander, have been arrested under suspicion of having helped a prisoner convicted of murder escape while being transferred to a hospital.

The prosecutor’s office said in a statement that the commander in charge of external security at the capital Skopje’s main prison of Idrizovo and three officers “helped and enabled the convict Bekim Memeti to escape." They are charged with “illegal release of a person deprived of liberty."

According to the prosecution, Memeti injured himself by cutting the palm of his hand late Thursday and, following the police commander’s instructions, he was sent without an escort to an emergency treatment center instead of being treated in the prison’s infirmary.

Procedure requires that if a convict needs to be treated in an outside facility, prison authorities must request a police escort.

Furthermore, and against the rules, Memeti was placed in the middle, which enabled him to grab the pistol from one of the prison officers and start shooting inside the van, injuring the driver and demanding that the vehicle stop. Mehmeti escaped with a car parked in front of the van and none of the prison officers gave chase.

An investigating magistrate ordered that three of the prison officers be placed in custody for eight days, while the fourth was banned from leaving the country. Custody could be extended as the investigation continues, and pending a trial.

Police are searching for the escapee and have issued a warrant. Memeti was sentenced to 20 years in prison a for murder committed in 2016. He has already escaped once before.