The Graham Dwyer murder trial is hearing evidence about two secret phones he is alleged to have used to contact Elaine O'Hara.
The 42-year-old architect from Kerrymount Close, Foxrock, Dublin denies stabbing the childcare worker at Killakee mountain in August 2012. Her skeletal remains were found in September 2013.
Crime analyst Sarah Skedd resumed her evidence today.
She used cell site analysis to compare the locations of three mobile phones allegedly used by Graham Dwyer.
They are his work phone, a prepaid 083 phone and a so-called "master" phone found in Vartry reservoir along with a "slave" phone.
The jury has heard that the 083 number was always active in the same locations as Graham Dwyer's work phone even when the architect was on annual leave in Co Cork on April 3, 2012.
There was evidence the two secret phones also appear to connect to cell sites in the south inner city of Dublin at times when the architect would have been at work on Baggot street.
Earlier today, members of the public were warned by Judge Tony Hunt not to live tweet from the trial while it is sitting in the absence of the jury.
He said the reporting restrictions are in place for good reason.