He is currently detained under the provisions of Section 4 Criminal Justice Act 1984 at a Garda station in Co. Cork.
It is understood he is being questioned, and must be either charged or released this evening.
This comes after skeletal remains were recovered from the former home of Ms Satchwell.
The suspected human remains have been removed to Cork University Hospital where they will be subject to further examination including DNA analysis.
A Garda technical examination at that residence is continuing and a second search at a location between Youghal and Killeagh, Co. Cork has been completed.
Ms Satchwell was reported as missing from her home on Grattan Street, Youghal, Co. Cork in March, 2017.
The case was upgraded to a murder investigation after “significant new intelligence” was brought forward.
Gardaí have continued their public appeal for any information relating to the murder of Ms Satchwell.
UPDATE: Gardaí have said that dental records indicate the human remains are that of Ms Satchwell.
