A 9-year-old girl was killed and two others were injured after a bomb, which they mistook for a ball, exploded.

The incident happened Saturday in Nandigram town of West Bengal in India. The girl and her two friends, both boys aged 9 and 10, were playing when they came across a round object in an abandoned house. The trio started playing with it. At one point, it exploded, The Telegraph reported. Bystanders took the three children to a local hospital.

Later, the 9-year-old girl, identified as Jahirun Khatun, was rushed to a private hospital in Kolkata, where she was pronounced dead. The two boys are reportedly in critical condition, The Times of India reported.

"The bomb was reportedly discovered near an abandoned home in the area, which had been under litigation for years. It seems the children had wandered inside," Kalicharanpur panchayat pradhan, Sohail Kazi, was quoted as saying by The Telegraph. "Why the bomb burst remains under investigation," he added.

It is unclear why and by whom the bomb was placed inside the building. A forensic team has joined the investigation and the abandoned building was further canvassed by a bomb squad to find any other unexploded device in the area, reported a local paper.

According to The Week, the explosive device was a crude bomb -- a type of device that uses a timer instead of an outside stimulus such as a radio frequency or a laser detonator. This category of bombs is made of improvised explosive devices and does not contain high-grade explosives. But, these bombs contain enough energy that can travel several hundred meters within a second.

District police superintendent Amarnath K. said Nandigram police have registered the incident as a case of unnatural death. The investigation remains active.

Earlier this year, a Michigan father pleaded guilty to charges of possession of an unregistered destructive device or pipe bomb after a homemade bomb he designed accidentally exploded in his teen son’s classroom. The son lost his thumb after the bomb went off in his hands and several other students sustained minor injuries.

Abandoned Building | Representative Image CC0 Creative Commons