The man and two women were arrested in relation to the case yesterday.
Three people held in relation to in relation to the murder of William Delaney have been released without charge.
The 56-year-old was last seen in Monasterevin in January 2019, but Gardaí were later told he had been killed and buried in County Laois.
A search of land around the Rock of Dunamaise did not lead to the discovery of his remains.
A man in his 30s and two women in their 30s and 50s have been were arrested as part of the investigation yesterday.
Gardaí say they believe people in the community have information and are yet to come forward.
Laois Gardaí Thanking Public After Finding Missing Woman
Missing Laois Teenager Found Safe And Well
Man In His 90s Dies In Laois Crash
Offaly Prize Bonds Holder Wins €500k
BNM Workshop Reunion Taking Place In Offaly Tomorrow
ICTU Reminds Employees Of The Right To Disconnect
Laois Town To Host Famine Commemoration Event
Plans For Billion Euro Data Centre In Westmeath Face New Appeal
Westmeath Councillor Advocates For More Remote Working Hubs
Midlands Homelessness On The Rise
Hundreds Without Power In Westmeath
Westmeath Domestic Abuse Support Service Reports Rise In Cases
Laois TD Highlights GP Gap
Call Made For 'Cost Of Disability Payment' in Budget 2027
Offaly Coffee Shop Listed Among Top 100 In Europe
Man To Stand Trial Over Midlands Tasering Accusation
Another Report Underlines Midlands House Price Inflation
Midlands Braced For Severe Thunderstorms
Sustainable Livestock Village Programme Launched For Tullamore Show
Offaly Woman Named National Carer Of The Year