An 8-year-old boy was killed in an explosion after a hand grenade was thrown through the window of an apartment building in Gothenburg, police said Monday.
"Many children and adults were in the apartment. It could have been much worse," a Gothenburg police spokesman told Swedish radio.
The boy was visiting the family who lived in the apartment and was sleeping in the living room when an unidentified assailant threw a grenade through the window.
Authorities suspect that a gang war could be behind the attack.
A man registered at the address was convicted of killing two people at a Gothenburg restaurant in March 2015, the spokesman said. "We will see if the motive is connected," he said.
Investigators traced the 2015 crime to a feud between rival gangs.