According to the European Agency for the Operational Management of large-scale IT Systems in the Area of Freedom, Security and Justice (eu-LISA), the agency in charge of managing SIS II, the total number of alerts inserted in the SIS increased from 50 million to almost 71 million between December 2013 and December 2016. However, the number of alerts on persons has remained low (about 0.8 million) in the period of reference. The majority of alerts on persons concern refusals of entry or stay (see figure 5). Currently, the SIS does not have specific alerts on foreign terrorist fighters (FTF). The number of alerts regarding persons for whom discreet or specific checks, which are relevant for detecting foreign terrorist fighters, are necessary, has increased only slightly, from 41 097 to 69 475, between December 2013 and December 2015. According to a note presented by the ECTC in April 2016 not all Member States insert data on FTF into the SIS systematically and, when they do, the information recorded is often incomplete. For example, although all perpetrators of the Paris and Brussels attacks were subjects of SIS alerts, the information entered was insufficient and, in the absence of biometric identifiers, the attackers were able to travel under a false identity and thus avoid being stopped at the border.