OSAKA -- A man arrested in August on suspicion of being involved in a slaying in June in Kadoma, Osaka Prefecture, was released after three days when an investigation determined his innocence, police said Friday.

Osaka Prefectural Police have officially apologized to the unnamed 45-year-old man, who was arrested in connection with the slaying of Satoshi Kin, 40, on June 14, they said.

Kin was allegedly beaten to death by a group of eight people in a bar owned by a friend after one of the assailants, who worked at the bar, had quarreled with Kin's friend over his salary, they said.

The man, a friend of Hajime Futori, who was taken into custody as the principal suspect in the case, was arrested in connection with the slaying in late August, even though he denied being involved.

He was released three days later when another suspect was identified and police determined the man had nothing to do with the killing.

Of the eight suspects in the case, four have already been indicted, while police are still questioning the remaining four.