A high court acquitted a nurse in Fukuoka Prefecture on Thursday of injuring two elderly patients with dementia whose nails were removed while she cut them in 2007, recognizing her act as "necessary and proper" nursing care.

In scrapping a lower court decision that found Satomi Ueda, 44, guilty and gave her a suspended prison term, the Fukuoka High Court also raised doubts about the credibility of her confessions to investigators in which she said she intentionally removed the nails of the female patients, aged 89 and 70.

"Some suspicions remain that the confessions could have been either forced or led" by the investigators, presiding Judge Hiroo Suyama said in handing down the ruling.