Between 2010 and 2017, Bruce McArthur, a Toronto based landscaper, tormented Toronto's gay village. He preyed primarily on vulnerable men who struggled with addictions, homelessness and their sexuality. It took nearly a decade to capture the Canadian serial killer, who then went on to murder eight innocent men. 

But why did he go undetected for so long? 

References:
https://en.wikipedia.org/wiki/2010%E2%80%932017_Toronto_serial_homicides
https://www.theguardian.com/world/2018/jun/23/bruce-mcarthur-toronto-gay-serial-killer 
https://www.oxygen.com/catching-a-serial-killer-bruce-mcarthur/crime-news/how-toronto-cops-caught-bruce-mcarthur