Complex sentence: She is killed by being dragged into her bathtub, and drowned by Takeo's evil spirit while her mother was unpacking but upon hearing a struggle she returned to find Brenda had vanished.
Split into simpler sentences: She is killed by being dragged into her bathtub, and drowned by Takeo's evil spirit while her mother was unpacking. Her mother returned upon hearing a struggle she returned to find Brenda had vanished.