A man in his twenties was arrested on Tuesday evening in Ballina in connection with a fire which occurred in an apartment in Belmullet in the early hours of Monday morning.
A man, who was in the apartment when the blaze broke out, was brought to Mayo General Hospital and was later discharged.
The scene was preserved for a technical examination.
On Tuesday before 5pm, a man was arrested in Ballina in relation to the incident. The man was detained in Ballina Garda Station under Section 4 of the Criminal Justice Act and was later released without charge.
A file is now being prepared for the DPP.