Elaine O'Hara (17 March 1976 – c. 22 August 2012) was an Irish childcare worker who was murdered in August 2012 by architect Graham Dwyer. She was last seen alive at a public park in Shanganagh, Dublin, Ireland, on 22 August. The remains of her body were discovered on Killakee Mountain, south of Dublin, in September 2013. The investigation of her disappearance and later of her death was widely reported. The 2015 trial and conviction of Dwyer led to the circulation of evidence concerning O'Hara's and Dwyer's involvement in the BDSM sexual subculture. The evidence of Dwyer's sadistic sexual practices led to the murder being called one of the most shocking crimes in Irish history.