Peter Ham hung himself in his garage in 1975. He was the leader of the band. The band continued with some lineup changes, but in 1983, Tom Evans also hung himself. Peter and Tom collaborated and wrote the hit song 'Without You' that Harry Nilsson and Mariah Carey had success with.
(I just looked and found out that Air supply, Heart, and Shirley Bassey also recorded the song, but i've never heard their versions.)