Question: Which actress in the 2004 South Korean film about a police detective who investigates a murder case while struggling to hang onto his relationships with his wife and mistress, committed suicide?

Context paragraphs:
The Scarlet Letter (2004 film): The Scarlet Letter is a 2004 South Korean film about a police detective who investigates a murder case while struggling to hang onto his relationships with his wife and mistress.  It is the second film by "La Femis"-graduate and academic Byun Hyuk (Daniel H. Byun), and starred Han Suk-kyu, Lee Eun-ju, Sung Hyun-ah and Uhm Ji-won.  The film debuted as the closing film of the Pusan International Film Festival in 2004.  The film is based on novelist Kim Young-ha's short stories "A Meditation On Mirror" and "Photo Shop Murder".

The Case of Itaewon Homicide: The Case of Itaewon Homicide (Korean: 이태원 살인사건 ; translit.  Itaewon Salinsageon) is a 2009 South Korean film, based on the true story of the Itaewon murder case, which shocked Korea when Hongik college student Cho Jung-Pil was found dead at an Itaewon Burger King in 1997.  The murder was investigated in 1997 by CID Agents J. Choi, D. Zeliff, T. Barnes and B. Crow.  Two troubled U.S. teenagers—Arthur Patterson (the son of a former U.S. Army officer and Korean mother) and Edward Lee—became suspects and were convicted.  Patterson was released a year later in a special amnesty and Lee was freed a year after that due to lack of evidence.  The case never resulted in further convictions.  

The Penguin Pool Murder: The Penguin Pool Murder is a 1932 American pre-Code comedy/mystery film starring Edna May Oliver as Hildegarde Withers, a witness in a murder case at the New York Aquarium, with James Gleason as the police inspector in charge of the case, who investigates with her unwanted help, and Robert Armstrong as an attorney representing Mae Clarke, the wife of the victim.  Oliver's appearance was the first film appearance of the character of Hildegarde Withers, the schoolteacher and sleuth based on the character from the 1931 novel "The Penguin Pool Murder" by Stuart Palmer.  It is the first in a trilogy including "Murder on the Blackboard", and "Murder on a Honeymoon", in which Oliver and Gleason team up for the lead roles.

Harry Bailey: Harry Richard Bailey (29 October 1922, Picton, New South Wales – 8 September 1985, Mount White, New South Wales) was an Australian psychiatrist and hospital administrator.  He bore the primary responsibility for treatment of mental patients and drug dependent clients via deep sleep therapy and other method at a mental hospital in the Sydney North Shore suburb of Pennant Hills; he was its principal.  The treatment has been linked with the deaths of a total of 85 patients, including 19 who committed suicide.  Bailey committed suicide while he was investigated.  One of Bailey's clients was Australian rock and pop singer and songwriter Stevie Wright, who was being treated for methadone addiction and later committed suicide, a report that was later part of a 2013 documentary on "Australian Story".

Bong Joon-ho: Bong Joon Ho (, ] ; born September 14, 1969) is a South Korean film director and screenwriter.  His films include South Korean hits "Memories of Murder" (2003), based on a true-life serial murder case, monster movie "The Host" (2006), and his first English-language film, science fiction adventure "Snowpiercer" (2013).  His latest film is "Okja" (2017), a South Korean-American film, which competed for the "Palme d'Or" in the main competition section at the 2017 Cannes Film Festival.  "Okja" was subsequently released by Netflix on June 28, 2017.

True Confessions (film): True Confessions is a 1981 crime film directed by Ulu Grosbard, The film stars Robert De Niro and Robert Duvall as the brothers Spellacy, a priest and police detective.  Produced by Chartoff-Winkler Productions, it adapted from the novel of the same name by John Gregory Dunne, and loosely based on the Black Dahlia murder case of 1947.  Dunne wrote the screenplay with his wife, novelist Joan Didion.

Lee Eun-ju: Lee Eun-ju (22 December 1980 – February 22, 2005) was a South Korean actress.  She was the star of hit films including "Taegukgi" and "The Scarlet Letter".  She committed suicide at age 24.

Damo (TV series): Damo (; lit.  "Female Detective Damo in the Joseon Dynasty"; also known as The Legendary Police Woman) is a 2003 South Korean fusion historical drama, starring Ha Ji-won, Lee Seo-jin, and Kim Min-joon.  Set in the Joseon Dynasty, it tells the story of Chae-ok, a "damo" relegated to the low-status job of a female police detective who investigates crimes involving women of the upper class.  It aired on MBC from July 28 to September 9, 2003 on Mondays and Tuesdays at 21:55 for 14 episodes.

The Scarab Murder Case (film): The Scarab Murder Case is a 1936 film directed by Michael Hankinson.  It is part of a series of films about fictional detective Philo Vance.  Paramount Pictures intended for William Powell to portray the character, as he had in three prior Paramount films - "The Canary Murder Case" (1929), "The Greene Murder Case" (1929) and "The Benson Murder Case" (1930) - as well as "The Kennel Murder Case" (1933) for Warner Bros. However, Powell changed studios, and the role went to Wilfrid Hyde-White.

Louis Lingg: Louis Lingg (September 9, 1864 – November 10, 1887) was a German-born American anarchist who committed suicide while in jail after being convicted and sentenced to hang as a member of a criminal conspiracy behind the Haymarket Square bombing.  Lingg committed suicide in his cell with an explosive shortly before his scheduled execution.

Supporting paragraphs: Lee Eun-ju The Scarlet Letter (2004 film)
Answer: Lee Eun-ju