Two men were found dead in the courtyard of a Paris apartment building Friday, their throats slit. French police have launched an investigation into the slayings and have arrested one individual in connection with the killings.

According to reports, the two dead men are the father and brother to the arrested man, who it is reported by best-selling newspaper Le Figaro was heard to shout “Allahu Akbar”, and was wearing traditional North African dress at the time of the deaths.

A witness to the attack told Agence France Presse that he was at home when he heard “a man screaming for help”, which prompted him to look into the courtyard of his apartment building.

Les policiers font progressivement rentrer les habitants chez eux rue de Montreuil. pic.twitter.com/oRCXHb5xBL — Romain Baheux (@RBaheux) March 17, 2017

The man told the agency: “I looked out the window, saw a man on the floor, there was a lot of blood. There was another man standing beside him. He was dressed in white with a djellaba [a traditional robe]. He dropped his knife, knelt down and prayed until the police came to get him.”

Pompiers et policiers sont déployés rue de Montreuil où un homme est suspecté d'avoir tué deux personnes. pic.twitter.com/c2cQ9g7Tbd — Romain Baheux (@RBaheux) March 17, 2017

Another resident of the building on rue de Montreuil who was on his way out to go shopping also described the scene as he walked into the courtyard. The elderly man told local news: “I went out quietly from my house to go shopping. When I arrived in the lobby, I saw a body in the middle of a pool of blood lying on the ground in front of the mailboxes. It was a carnage. I went out and there I saw another person all stained with blood.”

Le Parisien reports the arrested suspect has not been taken to a police station but was instead transferred to a psychiatric ward, as he was found “unfit for custody”.

French police criminal investigation teams set up a cordon around the crime scene and inquiries into the motivation for the crime are ongoing.