A man died on Sunday after he picked up an object outside a Stockholm subway station that exploded in his hand, killing him and leaving a woman injured, police said.

Police believe the blast wasn't terror-related and launched a murder investigation, Reuters reported.

The man found the explosive device about 11 a.m. local time outside the Varby Gard subway station in Huddinge, a residential district that’s part of greater Stockholm, police spokesman Sven-Erik Olsson said. A woman who was standing next to the man received minor injuries to her face and both legs.

Authorities declined to comment on the explosive object, but local newspaper Aftonbladet said the device was believed to be a hand grenade, Reuters reported.

“There is obviously something that has exploded strongly ...But we will have to wait for the technical investigation,” the Swedish police spokesman said.

The Associated Press contributed to this report.