The person was arrested on Friday as a reasonable suspect, the lower level of suspicion.
"After this weekend's investigative measures, I have made a new assessment and now the suspicions have been strengthened," says Public Prosecutor Emma Häggström according to a press release.
District court documents show that the suspect was questioned over the weekend, and that the police also heard from the plaintiffs over the weekend. The suspect reportedly declined a lawyer, but was nevertheless assigned a defense attorney, according to documents.
The first case of illness occurred on October 25th of this year. A week later, two more people fell ill on the ward. All three had symptoms so severe that they required intensive care.
Later, the prosecutor announced that a fourth person is also suspected of having been poisoned and that the cases are linked.
The analysis of what poisoned the people is not yet complete, prosecutor Emma Häggström told TT on Saturday.
Reports to the Swedish Work Environment Authority that SVT Uppsala has received show that the employees had critically low levels of potassium in their blood.
Staff at the ward at the children's hospital were informed of the arrest on Friday.
"The Academic Children's Hospital continues to take measures to increase safety and security in the workplace, including through continuous information to staff, continued presence of guards and limited access to the premises," says Viktor Ekström, Head of Security at the Academic Hospital, in a press release.
Occupational health care is in place and HR supports staff and managers, Ekström further states.
