Thirty-seven cases of suicide involving the killing of pets and also other family members were analyzed. In all, 81 people, 74 dogs and 3 cats were killed. Seventy percent of the cases involved males killing family members and pets.
Herzog, Harold, How Many People who Die by Suicide First Kill their Pets? (2020), 'Animals and Us' Blog Posts, Psychology Today, 27 April 114. https://www.psychologytoday.com/us/blog/animals-and-us/202004/how-many-people-who-die-suicide-first-kill-their-pets