It is confirmed that Percy's death in the first episode was indeed a suicide. The crushing guilt of killing Bo, combined with her family's toxic silence and their involvement in a larger smuggling ring to maintain their power, led her to leap from the cliff.
The Sinner - 4x08 "Part VIII" - Series Finale Discussion Thread [S4E8] Part VIII
Ambrose discovers that two years prior, Percy Muldoon accidentally shot and killed Bo Lam during a heated confrontation on a boat. It is confirmed that Percy's death in the