Suspect Zero  welcomes special guest, John Allore.  Since 2002, Theresa's brother, John Allore – whose podcast, Who Killed Theresa?– has continued the investigation, identifying 14 other unsolved murders from 1975 to 1981 which he believes may be connected. Beginning in 2018, John Allore started to focus on other Quebec cases from the 1970s through the present era, cases that further suggest systemic failures in how investigations are carried out.  They also talk about Luc Gregoire, a Canadian serial killer, who looks to be a viable suspect.