“The woman has admitted to cases of murder and she did this during interviews already yesterday,” said Stefan Marcopoulos at Stockholm police.
He was unwilling to detail the reasons for why the woman killed her children.
“It can interfere with the continued investigation as we are still looking for witnesses.”
Anyone who was in the vicinity of the scene of the crime – Munkholmen in Sigtuna – and could have seen anything that could have a connection to the murder of the boys has been encouraged to contact the police.
Prosecutors filed a remand order for the 30-year-old mother on Thursday in the Attunda District Court.
The woman will also undergo a so-called paragraph 7 examination, according to several media sources, referring to an assessment of her mental health.
The brothers, aged four and eight-years-old, were found in the water near a dock, and their clothes were also discovered nearby.
The father of one of the boys reported the disappearance late Sunday evening, and police initiated a comprehensive search and rescue with sniffer dogs, a helicopter and divers.
While their clothes were found early in the search, their bodies weren’t located until Monday afternoon.
The mother was arrested on Monday morning shortly before the bodies were located by divers.
The killings have prompted a review of routines in Sigtuna municipality after is emerged that the boys had not attended their respective school and pre-schools this term (which began in mid-August).
It took 13 days without any contact from the mother before the school contacted social services regarding the absence.
According to the prosecutor the murder was committed on September 18th in Sigtuna.