Swiss prosecutors have ordered the detention of Jacques Moretti, co-owner of the Le Constellation bar, following a deadly New Year's Eve fire that killed 40 people, many of them teenagers. His wife and co-owner, Jessica Moretti, remains free under judicial supervision. The couple faces charges including negligent homicide and arson. Switzerland observed a national day of mourning with ceremonies and a minute of silence. International leaders also attended a memorial service, with calls for accountability for those responsible for the blaze.