Convicted killer Graham Dwyer has been writing letters to au pair from his prison cell

He's currently serving a life sentence for the brutal murder of childcare worker Elaine O'Hara, but Graham Dwyer has been sharing details about his day to day life behind bars with a Spanish pen pal.

The Mirror reports that the Foxrock architect, who had an obsession with the BDSM sexual subculture, has been writing to a young au pair from his cell at Midlands Prison in Portlaoise. A source told the newspaper Dwyer (43) has been boasting about spending his days doing meditation and yoga and working on his physique. “He claims it helps him relax." the source revealed. "He told her it helps him to build muscles too and that his abs are taking shape from yoga. “He has grown his hair long too and from the impression she has given likes to look his best all the time.” The murderer has also been keen to share details of his musical abilities with his pen pal, saying he practices his guitar playing daily. Despite the evidence against him, Dwyer, who was born in Bandon, Co. Cork denied that he stabbed Elaine O'Hara to death on August 22, 2012. Elaine O'Hara was last seen alive at a public park in Shankill, Dublin on August 22, 2012. Her remains were discovered by a dog trainer on Killakee Mountain, south of Dublin, in September 2013. Three days before the grim discovery was made, a bag containing handcuffs, clothing, a ball gag and restraints was found by anglers in Vartry Reservoir, Co Wicklow. Dwyer is said to be waiting to appeal his conviction.