Jess Bell, Daily Star, March 17, 2017

Cops have launched a murder probe after the gruseome discovery today in Paris’ upmarket 11th district.

The knifeman reportedly shouted ‘Allahu Akbar’ at the time of the double killing before he was arrested by police, French TV channel RTL reported.

Witnesses reportedly heard the man shouting as he launched the violent attack.

The father’s other son was arrested in connection with the attack.

The motive behind the attack is being probed by police.

Cops swarmed the area of the Rue de Montreuil in the east of the French capital earlier today.

Heavily armed police were pictured guarding the scene as officers set up a 200m cordon.

The knifeman was arrested by police at the scene.

According to RTL, he was detained in the car park of a nearby building.

A shocked resident told local newspaper Le Parisien: “I went down. I saw a body in the hall, a body in the yard and a third person sitting with the firemen and policemen around.

“There was blood everywhere.”

According to reports, the man stabbed his brother and father before sitting down next to their bodies.

Medics rushed to the scene and tried to save the victims, but they were pronounced dead from serious injuries.

Residents in the block said the family had only recently moved in.

It comes after an elderly priest had his throat slashed in Normandy in July last year.

France is on a high terror alert after a spate of violent attacks throughout Europe.

ISIS attackers killed 130 people in November 2015 after opening fire on the Bataclan theatre and restaurant-goers in the capital.