The case of a woman who was planning a violent attack at an undisclosed school in the city is now headed to the office of the prosecutor for charges to be considered.
Police in Helsinki say that their preliminary investigation is continuing and that the suspect is still in police custody.
Two others are also suspected of involvement in the thwarted plot; an individual who allegedly promised to give a weapon to the woman and another who allegedly took part in helping to plan the attack.
Police have not revealed at which school in Helsinki the plans were to be carried out, but said that they had been in touch with the principal.
The main suspect had reportedly been devising plans for an attack since March 2015. Upon announcement of her arrest on September 20, police said the woman would be indicted by November 1.
The woman reportedly admired the person who carried out the fatal school shooting in Jokela, which claimed the lives of two school staff members and six students in 2007. The 18 year-old gunman, Pekka-Eric Auvinen, took his own life at the scene of the attack.