Retired Garda John Wilson said today that up until February 2012, Ian Bailey and his partner Jules Thomas were under a level of garda surveillance "reserved for active criminal offenders".
He is the sixth witness to be called in the former journalist's wrongful arrest action against the State and Garda Commissioner over the murder of French film maker Sophie Toscan du Plantier.
John Wilson has told the High Court he checked the garda Pulse system after allegations of garda misconduct were raised in Ian Bailey's Supreme Court appeal against his extradition to France.
The retired garda said there were in the region of 150 incidents which include sightings of the former journalist and Ms Thomas having coffee at the English Market and shopping in Super Valu.
It is his belief that this level of scrutiny was organised at a very high level in An Garda Síochána.
He has told the jury, that in April 2012, while still a serving member of the gardaí, he made a complaint alleging malpractice in relation to the continued surveillance of Mr Bailey.
Mr Wilson, who retired last year, has said he never got a response.
His evidence continues tomorrow.