Stockholm A man in his sixties was killed and a woman, 45, was slightly hurt in an explosion outside a Metro station in a southern suburb of the Swedish capital.
Citing Swedish newspapers, several reports suggest the explosive device was a hand grenade.
Police spokesman Sven-Erik Olsson said witnesses saw the man, in his 60s, pick up an object off the ground "which promptly exploded". The couple had been cycling past the device when the man stopped to investigate it.
Police also said the man died at the hospital and that the woman was also taken to the hospital and had wounds on her face and both legs.
Police checked in and around the subway station after the blast to make sure there were no other explosive devices.
Mr Alvarsjo said Swedish police have "unfortunately" noticed a rise in the use of hand grenades by criminal groups.
On Sunday morning, police searched the area around the station, which was cordoned off as a bomb squad was called in to carry out an investigation.
Authorities said they did not think the blast was related to a terrorist attack.