A garda has told the Central Criminal Court that he found a set of keys linked to Elaine O'Hara in Vartry Reservoir in Co Wicklow, three days after her remains were found in the Dublin Mountains in September 2013.

Garda James O'Donoghue was giving evidence at the trial of 42-year-old Graham Dwyer, who denies murdering Ms O'Hara in August 2012.

Garda O'Donoghue returned to the bridge over the Roundwood reservoir three times, after a local angler handed in items that he had found in the lake on 10 September 2013.

William Fegan and two other men had found handcuffs, restraints, clothes and other items.  

Mr Fegan handed them into Roundwood garda station on 11 September after becoming concerned that something was not right.

Garda O'Donoghue told the court he went to the place Mr Fegan had found the items on 12 September.  

However, he said it was windy and he could not see anything in the water.

He returned on 14 September and climbed down as close to the water as he could get but again he did not see anything.

On 16 September he said the weather was much better.

He said when he looked over the bridge he saw a set of handcuffs partially submerged in the river.

He climbed down again and began searching with his hands in the water - he said the water was about 12 to 14 inches deep.

He said he felt a metallic object and pulled out a set of keys.

The jury has heard this set of keys included keys to Elaine O' Hara's apartment, her family home and her car.    

There was also a loyalty card for Dunnes Stores on the keyring.

He also found a leather mask, a knife, an inhaler and a chain with a ring on it.

He made inquiries with Dunnes Stores about the loyalty card and as a result of what they told him, he made further inquiries and found that Ms O'Hara was a missing person.

He contacted his senior officers and later returned to the scene to seal it off as a crime scene.

Earlier, local angler William Fegan said he would fish in the lakes at Roundwood regularly and would often drive around the lake to make sure no one was illegally fishing there.

He said on the evening of 10 September 2013, he stopped his car on the bridge and met his brother and another man.

He said they were looking at the lakes and commenting on how low the water was.

Mr Fegan said it was very unusual to see the water so low.

There would normally be 15 to 20 feet of water under the bridge, but on this day after the hot summer, there was about 12 to 18 of inches of water there.

He said the last time he had seen the water so low was about ten years previously.

He said they saw rope and a shiny metal object in the water. They thought at first it was a ring from a bull's nose.

They managed to fish a number of items out.

They included handcuffs, clothes including a blue hoodie and white vest, a gag, a blindfold and leg restraints - described in court as "bondage cuffs".

He said they took the items out of the water and left them on the wall.

He said he went back the following day.  

Mr Fegan said he had had a good think about what they had found and something was niggling at him that something was not right.     

He said he put the items into a bag and brought them to Roundwood Garda Station and handed them over to a garda.

The court was told a pair of glasses found by the garda underwater unit at Vartry reservoir in October 2013 belonged to Ms O'Hara.

A number of members of the garda underwater unit gave evidence of carrying out searches of the Vartry river and reservoir on 17 September 2013 and 7 October 2013.

The court heard that among the items found were two Nokia mobile phones and two mobile phone batteries as well as a pair of glasses and a pair of sunglasses, and a rucksack.

The retail director of Specsavers in Dún Laoghaire, Co Dublin said that the numbers on the frame of the glasses and the prescription relating to the lenses in the glasses, matched the records for Ms O'Hara.

A representative from Dunnes Stores said the number of the Dunnes Stores loyalty fob found on the set of keys found in the reservoir by Garda James O'Donoghue was registered to Ms O'Hara.

The court also heard from a representative from Applegreen petrol stations who confirmed that the number on an Applegreen loyalty card found on the keys was registered to Ms O'Hara.

The engineer in charge of Vartry Reservoir and Waterworks told the court water levels in the reservoir were unusually high in 2012 and the reservoir almost continually overflowed.  

Eamon Fleming said that summer was a particularly wet summer.

The following year, he said was very warm and the reservoir levels dropped significantly to very unusually low levels. 

He said the summer of 2013 was the driest since 1995.