MADRID - Investigators believe that Younes Abouyaaqoub, a 22-year-old Moroccan-born man sought by police, was the driver of a van that rammed into crowds last Thursday in Barcelona, killing 13 people, a Catalan government official said on Monday.Spanish police have been searching for Abouyaaqoub - the only one of 12 suspects still at large - for several days but authorities had yet to identify him as the man behind the wheel of the van.Asked on Catalan radio on Monday whether Abouyaaqoub was the driver, Joaquim Forn, who runs home affairs in Catalonia's regional government said: "This is one of the lines of enquiry. It's the main one. Everything points to that. Today we will explain the evidence and (explain) why we have come to that conclusion."Police carried out more raids overnight at homes in the town of Ripoll, where many of the suspects lived, Forn said.Others thought to be part of a 12-strong cell have been arrested, shot by police or killed in an explosion at a house in Catalonia a day before Thursday's van attack.