Ms O’Hara’s remains were found over the weekend in the Dublin mountains.
In the days previous, a number of items including one linked to her work and material which could have been used for restraint, were found in Roundwood, Co Wicklow, and handed into the gardaí.
A further search of the Roundwood area, including the reservoir, yielded more personal items including clothes believed to belong to Ms O’Hara.
A single woman, who had just been released from hospital when she disappeared, Ms O’Hara had been missing for 13 months.
Ms O’Hara was last seen leaving Belarmine Plaza in Stepaside on Aug 22 last year. She was later seen close to the railway footbridge at Shanganagh Park, Shankill.
Earlier yesterday, DNA tests confirmed that the human remains found last Friday were that of Ms O’Hara. Gardaí are treating it as a “suspicious death”.
Although there are no signs of violence on any of the bones, the remains were incomplete.
Her car, a Green Fiat Punto 05 D reg, was located by gardaí at Shanganagh Cemetery, Shankill, two days after she went missing.
Gardaí believe she had been to visit the grave of her mother around the time of the last confirmed sighting of her.
“We are treating it as a suspicious death,” said a Garda source.
“There were no signs of violence, no broken bones or stab wounds on the bones, but the remains are incomplete. We have no skull.”
He said the autopsy was incomplete and that they did not have a cause of death.
Gardaí will now concentrate on how Ms O’Hara got from Shanganagh to a private forest in Killakee near Rathfarnham, some 16km away. They will also piece together her last movements.
As part of this, the gardaí will examine whether Ms O'Hara had rowed with anyone before she vanished and who she may have been in contact with, including by phone.
Gardaí are continuing searches on land near the site where the partial remains were found.
* Anyone with information can contact Blackrock Garda Station on 01 6665200,or the Garda Confidential Line on 1800 666111.