The trial of architect Graham Dwyer for the murder of Elaine O'Hara has resumed at the Central Criminal Court.

Mr Dwyer denies the murder of Ms O'Hara at Killakee Mountain in Rathfarnham on 22 August 2012.

The court heard further evidence this morning from Conor O'Callaghan from Vilicom Engineering Limited.

He provided data to gardaí in relation to 458 cells on the O2 network through which mobile phone calls are routed.

He also provided maps of the coverage of 46 of these cells in the Dublin area.

Mr O'Callaghan also provided data relating to a 086 phone number registered to Ms O'Hara as well as another 086 number.

Under cross examination by lawyers for Mr Dwyer, Mr O'Callaghan agreed that if you were making a call you would not necessarily be serving on the closest cell to you, especially in densely populated areas where there might areas of overlapping coverage.

Mr O'Callaghan said there had been no physical changes to the 46 cells examined since 2011/2012 - the time period for which he had been asked to provide data.

He said the mobile phone operators had invested millions of euro in their networks and it was very important to them that they were represented as accurately as possible.

Jamie Clifford from the 3 network gave evidence about data provided relating to a 083 number.

This prepaid mobile phone was bought on 25 March 2011 the court has heard.

Mr Clifford also gave evidence about top ups bought in connection with this mobile phone number.

Mr Clifford also made cell site information available in relation to 27 cell sites used by the 3 network.

The court heard he also provided data in relation to a 087 mobile phone number.

He said this was registered to A&D Wejchert and Partners and the contract ran from April 2011 to October 2012.

He provided call data in relation to this number between 7 October 2011 and 30 November 2012.

The court also heard evidence from Kevin Dowling from Vodafone.  

He gave data to gardai in relation to 72 cell sites, and also created graphs of the coverage of a number of cells including Deansgrange, Johnnie Fox's in the Dublin Mountains, Belarmine, Dublin City Centre and Roundwood.
 
This afternoon, lawyers for Mr Dwyer accepted he was the registered owner of five vehicles at various times from November 2010 to date.

The court was told a toll road tag registered to Mr Dwyer was used on the road from Dublin to Galway and back again on 4 July 2012.  

The court was also told a toll registered to Mr Dwyer was used at toll plazas on the M7/M8 and the N8 and back again on 3 April 2012.

George Ryan of Carron Model Flying Club in Co Clare gave evidence that Mr Dwyer attended an event at Carron on 8 July 2012.

Mary Dorrian of Dorrians' Imperial Hotel in Ballyshannon in Co Donegal gave evidence that Mr Dwyer had checked in to the hotel on 5 July 2012 and left the next day.

There was also evidence from Colm Costelloe, a friend of Mr Dwyer's since childhood, that they had had a night out with friends on 2 July 2011.

The case will resume on Monday.