The National Security Committee (KNB) issued on May 22 an arrest warrant against Frank Monstrey, a Belgian businessman. The KNB opened an investigation two days before in Astana, without disclosing the nature of the case. Between 2004 and 2017, Monstrey held a stake and a managerial position in Zhaikmunai, an oil company operating in the north-west of the country, later renamed Nostrum Oil & Gas. An OCCRP investigation in 2018 revealed that companies tied to him were the source of around $440 million, which was subsequently invested in real estate and businesses in the United States.