When she purchased an anonymous pre-paid mobile phone number, she received a threat on it a day later. Messages had come in Dutch, English and "broken Arabic", she said.
The Jordanian-Swedish citizen had also been called on a family member's pre-paid Jordanian number while staying in the country, while a relative in Sweden had been called and told that Kiswanson would be "eliminated".
Human rights organization Amnesty International said it was forced to temporarily close its office in The Hague for security reasons after an employee's personal e-mail was hacked and used to send Kiswanson a death threat.
Since the start of 2015, the ICC has been conducting a preliminary examination of possible crimes committed by both sides in the Gaza conflict.Although the war crimes court's cases are always highly contentious, rights workers have never before been threatened in the Netherlands. Dutch authorities confirmed they were investigating threats against Kiswanson, first reported publicly by newspaper NRC Handelsblad, and that they had put in place measures to protect her. Activists and witnesses linked to ICC cases have been threatened in the past. Judges at the court have said threats against witnesses contributed to the collapse of the crimes against humanity case against Kenyan President Uhuru Kenyatta last year.