TAIPEI (AFP) - A Taiwanese man has been arrested on suspicion of murdering his grandmother with a hammer, seven years after he killed his father using the same weapon, police said on Saturday.

The man, identified by his family name Lee, has a history of mental illness and allegedly attacked his 85-year-old grandmother on Friday, hammering at her head and face while stabbing her eyes with a screwdriver in their house in southern Taiwan, police said.

When police arrived at the scene, they found the grandmother lying dead on the floor. Her face was bloody and disfigured while Lee's face and hands were dotted with blood.

Lee, 35, claimed he suffered hallucinations and that he would have "gone outside to kill somebody else" if he did not kill his grandmother, the Apple Daily newspaper reported.

Lee was arrested in 2007 for murdering his father with a hammer, claiming he was angry that the victim had an affair and had abused his mother. He was not indicted as he was deemed to be in a state of insanity and was ordered to be hospitalised for five years.

Lee has been in and out of hospital for the past two years and two weeks ago, his mother arranged for him to come home to spend some time with the family. He was scheduled to be re-admitted on Monday, the newspaper said.