The boy was reportedly arrested on Thursday last week.
"I can say that it was under calm conditions," district attorney Olle Sjölund Smitt tells the newspaper.
According to the newspaper, it was the boy's school that raised the alarm. The school confirms that a police report has been filed, but does not comment on what it concerns.
The suspected crime period runs from September 10 to October 22.
Since a law change on September 10, 14-year-olds can be detained and sentenced for crimes carrying a minimum sentence of four years in prison.
