A divorced British father with a history of drunkenness and domestic violence was formally accused of the murder of his two children, who were found with their throats cut in his apartment in southern France.

Julian Stevenson, 47, an unemployed salesman with a business degree, made a brief, private appearance before a prosecutor and an investigating magistrate at the Palais de Justice in Lyon yesterday afternoon.

Stevenson had lived in France for 10 years. He was banned in 2010 from seeing his children, Mathew, 10, and Carla, five, without the presence of his wife or a social worker. This ban was lifted recently and Stevenson spent Saturday with the boy and girl.

Download the new Independent Premium app Sharing the full story, not just the headlines

Officials in the prosecutor’s office said that there was no reason, at this stage, to believe that the murder of the two children was planned or premeditated. Stevenson was therefore placed under formal investigation – a step short of a charge – for the “voluntary homicide of minors”.

Stevenson, acrimoniously divorced from the children’s French mother, has admitted killing the children during his first solo parental access for three years.

The officials said that the investigation, which could take several months, might yet decide that he planned the killings. He would then face a more serious charge of assassinat or “premeditated murder”.

The investigating magistrate will also consider whether any official, or officials, should face legal proceedings for lifting a ban on Stevenson spending time alone with his children.

Neighbours said that the trio were seen wandering around the Lyon suburb of Saint-Priest apparently happy and relaxed. Stevenson bought the children sweets and did not appear agitated or upset.

When his ex-wife, Stéphanie, came to his apartment to collect the children, she found Stevenson on the communal stairs with bloodstains on his clothes. According to neighbours, he fled on roller skates. Police broke into the flat and found the bodies of the children.

Stevenson was arrested on the street in the centre of Lyon several hours later. Investigators said that he had confessed to the murders on Sunday.

“He told us exactly what had happened but would not discuss his motive,” an official in the state prosecutor’s department said yesterday. Other officials have said the crime appeared to be “linked to his acrimonious separation” from his family and his restricted rights of access.

According to local press reports, Stevenson moved to France about 10 years ago. He was a business graduate who had once had a job as a “commercial representative” but had been unemployed for several years.

Stevenson’s rights to see his children were restricted by court order in 2010 after he struck his wife. She moved with the children to the Isère département (county), 70 miles east of Lyon, after their divorce in 2011.