Sapporo Nishi Police in Hokkaido arrested a 26-year-old man Tuesday for allegedly striking his 4-month-old daughter in the head on several occasions to the point where she has been unconscious since August.

Toshiyuki Miyamoto of Sapporo's Nishi Ward reportedly abused his daughter, Yuki, for roughly a month starting in early July. He told police that he physically abused his daughter to relieve his stress.

The infant went into convulsions on Aug. 5 and was taken to a hosiptal by her parents. She has been unconscious since then.

Hospital staff found bruises on her head and body and alerted a child consultation center, but Miyamoto's 22-year-old wife told Kyodo News that she was not aware of the abuse nor the bruises on her daughter's body.

According to his wife, Miyamoto quit his job at a construction firm in July because he had trouble with his colleagues and was staying at home since then.