A child was dead and another fighting for life after they were allegedly stabbed by their father and thrown out of their apartment window in Sweden.

Stockholm police arrived at the scene Sunday night after being alerted by local residents and found the two kids below the age of 10 lying in a pool of blood outside the building. Both children were immediately airlifted to a nearby hospital but the younger child succumbed to injuries on the way, Sky News reported.

In the meantime, forensics officers entered the apartment and found blood in the bedroom. They also seized clothing from the apartment.

A case of murder and attempted murder was registered and two people - a man and a woman – were taken into custody. Cops said the accused had a relationship with the children but did not give out details.

Local media reports stated the father stabbed the kids in their beds while they were sleeping and threw them out the window 50 feet above ground. The father, who is believed to be in his 40s, reportedly stabbed himself after that.

Meanwhile, speaking to local outlet Expressen, a neighbor who heard a commotion coming from the apartment, said, "It sounded like a mess, more that something fell to the ground than screams."

"I did not hear any children screaming. But it was very short so I did not think much about it," he added.

Another neighbor described the father of the children as "nice and accommodating.”

Investigation into the incident was ongoing and the other child remained critical as of Monday night.

Last year, a woman in the southern Indian state of Karnataka killed her seven-day-old infant granddaughter by throwing her from the rooftop because she was unhappy with the gender of the baby. The infant's mother had left the child in the care of the accused while she went to the washroom. When she returned, the baby was missing. The infant was found lying motionless on the ground in a pool of blood.

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In this image, a police tape is photographed in Chester, United Kingdom, July 4, 2018. Christopher Furlong/Getty Images