The Fifth Mind (2007)

In search of the truth about her father's death, Katherine visits the murderer - her long forgotten brother, Daniel - who serves his time in prison. However, she is faced with a man who suffers severe multiple personality disorder. Determined to piece together her own clouded memories, Katherine struggles to win Daniel's trust and find out the truth of what really happened on the day of the murder. But as family secrets and repressed memories resurface, Daniel's last vestige of sanity starts to crack and Katherine must confront the fifth personality who holds the secret, not only about the day of the murder, but also about the one childhood memory that shaped and tainted the rest of their lives.