Police at first thought that Alma Gabriela Knutsen had drowned by accident when her body was found floating in the Søgneelva river near Kristiansand in Norway almost two weeks ago.
The body was discovered by kayakers out paddling.
As the police investigated, however, they found more and more technical evidence that pointed to foul play.
The girl's family suspected that Alma's death was not an accident from the start.
“They had a bad feeling about what had happened to her,” Terje Pedersen, an officer with the local police told Norway's Dagbladet
Yesterday, a 14-year-old boy admitted to police that he had killed the the young girl and that the two were “young people who knew each other”.
“Based on the information the boy has given in questioning, we consider it to be a murder,” Terje Kaddeberg Skaar, a prosecutor with the Agder police told national broadcaster NRK
Both of the young people were from the small town of Søgne with a population of about 11, 000.
“They were the same age, and youth circles are small here,” Pedersen told Dagbladet.