People gather at the makeshift memorial near the scene of shooting —AP

Agencies STOCKHOLM

Swedish police are  still working to establish a motive for the gunman  who carried out the “'worst mass shooting” in Sweden's history and  is among the 11 dead.  Investigators said they were trying to piece together exactly what happened in the city of Orebro  Västhaga district on Tuesday.  

They believe the attacker acted alone and turned the gun on himself after the rampage, according to the Daily Mail. His relatives said he was a withdrawn loner who was unemployed and “having a hard time”Authorities are yet to reveal the shooter's identity, but relatives speaking to Swedish press painted a picture of a troubled recluse who had lost contact with his family and friends. 

The shooter also legally changed his name eight years ago - a move that took family members by surprise. “We haven't had much contact with him in recent years. As a child he was different but lively. He did well in school,'”one relative said. “But in recent years he has had a hard time. He is not working.”

Another added: 'He's really a loner. He used to have a friend he hung out with a lot, but not now. He wants to be by himself. He doesn't seem to like people.' They went on to say that the shooter had little contact with his parents who are “out travelling a lot”, but that he liked to “take care of their dog”. A team of armed cops conducted a raid on the suspect's house on Tuesday but refused to provide details of the raid.

TV4 claimed the shooter had no previous convictions and was not known to the authorities.  He also possessed a firearms licence. The King of Sweden, Carl Gustav,also paid tribute to the victims in a statement from the Royal House. The King and Queen were expected to visit the site, the BBC said. Flags were flown at half-mast outside official buildings in some parts of the country, BBC said.