Sean was killed by Charity McLanden in Another Simple Favor. Charity is revealed to be the third triplet sister of Emily (also known as Hope) and Faith, who was believed to be stillborn but was secretly raised by their Aunt Linda. Charity used her resemblance to Emily to disguise herself and killed Sean by injecting him with a fast-acting poison through his fingernail while he was in the shower, causing him to collapse and die
. Charity also killed Dante, Emily's new husband, by shooting him multiple times during the wedding reception. She lured Dante away by pretending to be Emily or by using the promise of a rendezvous with his secret lover, then killed him to protect her own interests and continue the deception
. Thus, Charity is the killer of both Sean and Dante in the movie, motivated by a complex family conspiracy and her own agenda
