A man who stalked a woman and later talked about raping her young son was disconnected from reality and desperate for friendship, a court has heard.

Mark Mulligan (39) told gardai he had developed a fantasy world for himself because he was very lonely. He said that this led on to online conversations in which he discussed raping and torturing boys and girls.

Mulligan of Railway Road, Clongriffin, Dublin pleaded guilty at Dublin Circuit Criminal Court to harassment of a named woman at locations in Dublin on dates between 2008 and 2012. Mulligan also admitted possession of child pornography at his home on July 7, 2013.

He had pleaded not guilty to a third charge of producing child pornography at his home on dates between March 1 and March 17, 2013. Last month a jury of ten men and two women took 44 minutes to return a unanimous verdict of guilty.

The final offence relates to conversations with another person using the Skype internet programme in which Mulligan made sexually explicit references to RTE and TV3 “celebrities” and their children. Gardai discovered these automatically held transcripts of these “chats” during a search of Mulligan’s home as part of an investigation into a separate harassment case.

In that other case Mulligan sent a former colleague a threatening text message and an image of a dismembered doll as part of his “rape fantasy”. Last July he received a prison sentence of four years with one suspended for harassing and threatening to kill that victim on dates between August 2012 and July 2013.

Today Judge Patricia Ryan adjourned sentencing in this new matter in order to give the Probation Services time to assess him.

In text conversations with an unknown person over Skype, described Mulligan’s own barrister as a "disgusting fantasy conversation”, Mulligan said he would "love to rape" the three year old son of a woman he knew, because she “pissed” him off.

He then sent a non-explicit photograph of the boy to the other person. This other man, using the online identity rodub82, said: “Let’s snatch him”.

The accused replied: "mmmm make him watch us kill his mum and dad, and then kill him”.

Mulligan also asked about raping Irish celebrities and suggested “any of the reporters on RTE or TV3”. The other user replied “prefer their kids” and Mulligan agreed and said it would give them something to remember.

He later told gardaí that the conversations were all just “sick fantasies” and he never intended to act on them.

Mulligan had taken the image of the child from the woman’s personal page on a social networking website. This woman had made a complaint to gardai in 2008 about Mulligan’s continued harassment of her via text messages and emails.

Gardai told the woman there was little they could do at that point but she should keep a note of Mulligan’s actions.

In 2009 he set up a fake account on the social networking website Bebo under the name of an actual friend of the victims and contacted her from this. When she became pregnant Mulligan emailed her a note of congratulations.

In 2012 a third party contacted the victim because he had seen photographs of her being used on a fake Facebook account set up in a different name.

In a victim impact report the woman said she had to move away from where she lived because of the ongoing harassment.

She said she has been left deeply upset and traumatised by Mulligan’s actions.

She said she had developed a real sense of dread walking past Mulligan’s apartment because he would be out on his balcony watching her.

Garnet Orange SC, defending, said that his client had engaged in ongoing and deeply unpleasant stalking of the victim but has since expressed remorse and regret. He said a Probation Services report outlines how Mulligan experienced deep sense of loneliness and separation from the world and was in some ways disconnected from reality.

Counsel said that Mulligan had pleaded not guilty to producing child pornography because there was a contentious legal issue over whether or not the online text conversations between two private adults amounted to the production or distribution of child porn.