Police investigating Sweden's worst mass shooting were still trying to establish a motive as to why a lone gunman opened fire at an education campus in the southern city of Orebro, killing 10 people.

Swedish police found several rifles in the adult education centre in Orebro where a gunman killed 11 people and wounded several others this week in the country's deadliest mass shooting, a spokesperson said on Thursday.

One day after the killings at an adult educational center, some gathered to lay flowers and come to grips with the violence.

At least 10 people, including the gunman, were killed Tuesday at an adult education center in what Sweden’s prime minister called the country’s worst mass

Sweden is reeling from the country's deadliest mass shooting this week as investigators continue to look into the gunman's motive

The authorities said that at least 11 people were killed and that the suspect was believed to be among the dead.

Officials in Sweden have vowed to determine why a man killed 10 people, and apparently himself, in an unprecedented attack that's shaken their "society to its core."

The king and queen visited the scene of the tragic event that occurred on Tuesday and Swedish flags were flown at half-mast to honor the victims.

Around 10 people were killed in a school shooting in Sweden on Tuesday, Swedish police said. (Reporting by Anna Ringstrom, Louise Rasmussen, Stine Jacobsen, Johan Ahlander, Simon Johnson and Niklas Pollard,