A garda harassed a sergeant by sending her a Valentine card, emails and a friend request on Facebook despite numerous warnings from his superiors.
Gerardine Small, prosecuting, told Dublin Circuit Criminal Court that Gda Donal Maguire's harassment of the woman was not disputed. Rather, the jurors were told they would have to determine if he was suffering from a mental disorder at the time.
Gda Maguire (40), of Rock Road, Bundoran, Co Donegal, has pleaded not guilty by reason of insanity to two counts of harassing the woman in Dublin on dates between February 18 and March 11, 2012 and between August 1, 2012 and February 4, 2013.
Det Supt Walter O'Sullivan said Gda Maguire first met the sergeant at the Dublin station where he worked in 2011.
In February 2012, the woman received a Valentine card signed by the accused which stated he never dreamed how wonderful his life could be until the day "you came along".
He said she meant the world to him and he signed it with "love and eternal gratitude".
He had also transcribed the poem, The Cloths of Heaven, by WB Yeats on to the card.
The sergeant spoke with Gda Maguire privately, saying they were both married with children, she had no romantic interest in him and if he did it again she would report him.
She believed that would be the end of the matter, but he continued to contact her through email via the garda Pulse system.
One email began: "I love you and I want all your life into mine."
The woman contacted her superior and he spoke with Gda Maguire, who said he was very fond of the woman and had not meant to upset her. He said would not contact her again.
There was no communication for six months until she received an email, again via pulse, from Gda Maguire.
She was angry, but ignored it, but the following day she received another. At this point she realised she would have to make a formal complaint.
She reported the emails and Gda Maguire was disciplined. The emails continued, which resulted in his access to the system being revoked.
Gda Maguire turned up at a 10km race the sergeant was running in and her colleagues saw him staring at her.
Two weeks later she received a friend request from him on Facebook.
That was the final contact before the seriousness of the harassment was escalated and investigated as a criminal offence.
The sergeant was granted annual leave following the Facebook contact, as her superiors believed she was not in "a fit position to do her work".
Det Supt O'Sullivan agreed with Ronan Kennedy, defending, that when Gda Maguire was interviewed in June 2013, he said he was infatuated with the woman.
Gda Maguire had difficulty understanding what he had been doing was wrong.
He accepted that, following the interview, both he and his colleagues had concerns for Gda Maguire's well-being.
Ms Small told the jury it would hear this morning from consultant psychiatrist Dr Brenda Wright. She would testify that, in her view, Gda Maguire "didn't know what he was doing was wrong, was unable to appreciate the wrongness and was unable to refrain".
The trial continues today before Judge Elma Sheahan and a jury of three women and nine men.