Barcelona attack: Police hunt 18-year-old Moussa Oukabir in connection with Las Ramblas van attack

Detectives shift focus to younger brother of man detained on Thursday

Moussa Oukabir, from Barcelona, is the brother of arrested suspect Driss Oukabir (Kiwi)

Police in Spain have launched a major manhunt for an 18-year-old man wanted in connection with the terrorist attack in Barcelona that left at least 13 people dead and more than 100 injured when a van ploughed into crowds on the busy Las Ramblas street.

Suspect Moussa Oukabir is the younger brother of 28-year-old Driss Oukabir, who was arrested on Thursday night because the van used in the attack had been rented in his name.

Driss handed himself in to police in the town of Ripoll, around 65 miles north of Barcelona, after seeing his name being linked to the attack.

​The Oukabir brothers are of Moroccan heritage but now live in Spain: Driss in Ripoll and Moussa in Barcelona.

Police are reported to be investigating why the older brother did not report the alleged theft of his identification documents earlier. They are also looking into whether Moussa Oukabir was one of the five suspected terrorists killed during a police operation in the coastal town of Cambrils.

Two years ago, an account registered in the name of Moussa Oukabir posted regularly on a question-and-answer website called Kiwi. In response to a question asking what users would do if they ruled the world, he wrote: "Kill the infidels and leave only Muslims who follow the religion."

Asked where he would never want to live, he replied: "The Vatican".

Spanish police have arrested three men in connection with the attack but none are believed to be the driver of the van. In addition to Driss Oukabir, a Spanish man was arrested in Melilla and another in Ripoll.

Five suspected attackers wearing fake suicide belts were shot dead in Cambrils after ramming into people with a car in a second attack, leaving seven people injured.

Isis has claimed reasonability for the Barcelona attack, although the group has a history of saying it was behind attacks that were carried out by "lone wolves".