A man arrested in connection with a fatal fire that claimed the lives of a couple and two children has been released without charge.

Kim and Phillip English and their sons Callum and Jayden died in the fire in their home in the Birchwood area of Waterford on October 13. Gardaí are treating their deaths as murder.

Two other children were critically injured in the blaze.

The arrested man, aged in his 20s, was released pending a gardaí file being prepared for the Director of Public Prosecutions (DPP).

He is the sixth person to have been arrested in connection with the fire.

A man in his 50s and two women in their 30s arrested by gardaí last week were released without charge at the weekend.

Files are also being prepared for the DPP for those three individuals.

Earlier this month, a man and woman appeared in court charged in relation to the attack.

Jessica Dalton, 31, with an address in Waterford city, and Cian Stacey, 21, of no fixed abode, were remanded into custody charged with one count of criminal damage and two counts of assault causing serious harm.