A 3-year-old girl in Alaska died and her 1-year-old sister suffered from hypothermia when their mother and boyfriend locked them up in a bedroom with a window open to -30 degrees C, MSNBC reported.

Their mother, 28-year-old elementary teacher Esther G. Edwards-Gust, shares an apartment with her boyfriend Richard Tilden Jr (29) and the children in the Inupiat Eskimo community of Barrow. The toddlers were locked up as a punishment for wetting their beds.

The children were taken to hospital Feb. 2 when Tilden found that the elder child was not responding. He called 911. Both children were diagnosed with extreme hypothermia and flown to an Anchorage hospital, where the 3-year-old died.

Tilden later told authorities that he had been drinking the night before and had opened the window to air out the room since the girls had wet their beds.

He added that the door's latch from the inside of the room was broken, and hence it was impossible for anyone inside to open it.

Tilden has been arrested and a warrant has been issued for Edwards-Gust's arrest.