A doctor in Berlin, Germany has been arrested for allegedly killing 4 of his elderly patients under his palliative care and setting fire to their houses to try and destroy evidence, according to local authorities on Wednesday.

Police did not name the suspect due to Germany's privacy laws but disclosed he is 39 years old and was part of a nursing service's palliative care team, per ABC News. He has been in custody since Tuesday pending an indictment for suspicion of manslaughter, one count of arson and three counts of attempted arson.

The doctor allegedly carried out the killings between June 11 and July 24. His victims were all female, aged 72 to 94. On June 11, he allegedly killed an 87-year-old woman, per Bild, after setting fire to her house. Emergency workers were unable to resuscitate her and she died in the hospital shortly after. On July 8, the doctor allegedly killed a 76-year-old woman before attempting to set fire to her apartment, however the fire went out on its own. He then reportedly called one of the woman's relatives and tried to claim he was standing in front of her apartment when the fire started. His other 2 patients, aged 94 and 72, he allegedly killed and set fire to their homes on July 15 and July 24, respectively.