Hong Kong (CNN) A former nursing student murdered her parents before killing herself on Father's Day, according to Hong Kong police, who suggested her skin condition may have motivated the attack.

An initial police report found that the 23-year-old had attacked her parents, inflicting fatal wounds to her father's chest, and her mother's chest, waist and legs.

Their bodies were found by police after a relative called authorities, telling them that no one had answered the door at the apartment in Tuen Mun, a residential neighborhood of Hong Kong.

A 30-centimeter knife, which was suspected to have been used in the attack, was recovered at the scene, police said.

The couple's daughter Pang Ching-yu was also found dead at the scene. Police said they found a suicide note in Pang's bedroom saying she was bothered by long-term eczema.

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