These were the words of Joe O'Reilly just weeks after the murder of his wife Rachel at what he called their "dream home" in The Naul, north county Dublin.

O'Reilly has now been exposed as a liar, and a jury has decided that he did in fact murder Rachel and he will now spend at least 20 years behind bars.

I probably know Joe O'Reilly better than any other journalist. I have spoken to him on well over 20 occasions and wrote nearly as many front page stories on the murder that has both shocked and captivated the nation.

I first wrote about Rachel O'Reilly the day after she died on 4 October 2004.

Detectives initially believed she had been murdered during a burglary that went wrong. Joe's alibi checked out and he was not considered a suspect.

Gardai had not made a breakthrough nearly two weeks after the murder and wanted Joe to make a public appeal to encourage people to come forward with information. I was the journalist through whom this appeal was going to be made, and I drove to Rachel's parents' house in my capacity as crime reporter with the Evening Herald.

Rachel's mother Rose Callaly welcomed me and brought me into a room to the side of the kitchen where I was introduced to Joe. Rose was overcome by emotion and left the room and closed the door, leaving me alone with the grieving husband. I was immediately struck by his massive height and sheer physical bulk, but there was a weakness in his handshake and his eyes looked dead, as you might expect from a man who had just lost his wife of nearly eight years.

Joe wore jeans and a baggy fleece jumper. The two of us sat in private for about an hour and he opened up to me about Rachel. He told me about what a good mother she was and that she had already bought the children's Christmas presents even though it was only October.

He said she "lived for the boys" despite the fact his mother had recently made a complaint to the social services about the way Rachel treated her children.

Joe also told me about the trip they were planning to take to Canada. He was very passionate about his two sons and confided that his four-year-old son Luke asked, "Where is Mammy? Is her head sore? Is she under the ground? Is she a ghost?"

Explicit details It surprised me that Joe was willing to go into explicit details about the day of the murder and seeing his wife lying dead in their home. He told me, "When I saw her body I just went into automatic pilot, I guess, trying to revive her. You just don't think. She was cold and stuff, but you just wouldn't think that a 30-year-old is dead . . .

your wife's not meant to be dead. It didn't make sense. I just couldn't come to terms with itf Someone killed her in cold blood for no reason that I can see. What's to stop them doing it again? This is worse than anything I have ever imagined. Absolutely nothing can prepare you for this."

He also spoke about their home where the murder took place: "Cleaning up the house on Saturday was bad. Cleaning the blood from the walls and taking up the carpet and burning it. It was terrible but I knew it would be."

Throughout the interview, Joe never cried or really showed any sort of emotion.

He stared into space as he spoke and was very calm. Although he wasn't a suspect, I wasn't totally convinced he was innocent, but I put his almost robotic coldness down to shock.

Getting the first interview was a big deal and when I arrived back in the office I was immediately surrounded by colleagues all wanting to know what he was like. I remember saying: "If it turns out that he did it, I won't be a bit surprised."

After our first encounter, we swapped phone numbers and I told him if I could do anything for him to just give me a call. We agreed that I would contact him the next day after the interview appeared in the newspaper.

I rang Joe after the paper hit the streets and he was delighted and very grateful, saying he hoped it would lead to the killer being caught. We chatted for a while and ended up talking about his home in The Naul, where the murder had taken place.

To my complete amazement, he suggested showing the newspaper around the bungalow which he said was still covered in Rachel's bloodstains. I couldn't believe it and thought this was psychotic behaviour, but as a journalist it was a fantastic story.

Herald photographer Kyran O'Brien spent an afternoon taking pictures of the house where, just a few weeks before, 30-year-old Rachel had been beaten to death.

'This is where it happened' Joe matter-of-factly pointed out bloodstains on walls and posed for pictures without displaying any emotion. He let us into the bedroom where the murder took place and calmly stated, "This is where it happened."

Looking back now, it was the textbook behaviour of a psychopath, going back to the scene of the crime and taking trophies.

Only his trophies were photos that were seen by 320,000 newspaper readers when they appeared on the front page.

Joe was happy with the way he was being portrayed in the newspaper articles and began to trust me. Over the next few weeks, we spoke every day or two. I am not naive and know that he wasn't taking my calls or ringing me because he needed to talk to somebody. He was using me to see what the gardai had on him.

I heard from several sources that the gardai were investigating the sighting of a dark-coloured car around The Naul on the morning of the murder. When Joe read that, he asked me about it the next time we spoke. He said: "I see the guards are trying to trace a dark car. You know, I drive a dark car. Do you know anything else about it?

Who do you think it was?"

O'Reilly said the guards were not talking to him or keeping him up to speed on what was happening in the investigation.

Basically, he was tapping me for everything I knew about what the police were doing. I told him little bits and pieces of what I knew and he was always very curious and constantly asking questions.

There was a good reason why the investigation team was not talking to Joe at this stage: by now he was the main suspect . . .

indeed, the only suspect. Sources told me they were certain he was the killer and what looked like his car had been caught on CCTV around The Naul and other areas of north Dublin when he was supposed to be in Broadstone.

On 26 October, just over three weeks after the killing, I first wrote that gardai had now ruled out the possibility that Rachel's murder was random and said she knew her killer. I also discovered that Joe was having an affair with Nikki Pelley and I rang him and told him about the rumours doing the rounds. I had researched Pelley's background and there was no doubt in my mind that the stories were true. The following day, Joe told me, "There is no other woman in my life and I have never had an affair, absolutely and definitely not.

I had heard that I'd been involved with an acquaintance and the like, but this is 100% untruef I was asked the question by the gardai and I told them 'absolutely not'. I never had an affair on Rachel and I've told the guards this. I am upset enough at the moment and I do not need this." In fact O'Reilly had admitted to detectives that he was seeing Nikki Pelley and he was telling barefaced lies.

We later spoke about the fact his wife was probably killed by somebody she was familiar with. His response was emphatic:

"I cannot believe it. Unless the person they catch has horns and a pointy tale, I will not believe it. The murder was so brutal and inhuman that I simply cannot imagine someone she knew doing it. If it is someone that we both know, I will be shocked, probably physically sick as well. The murder was so vicious, beyond imagination. The whole thing is surreal."

Two possible suspects Joe even told me he had offered the names of two possible suspects to gardai, and said, "I will gladly apologise to them when the murderer is found but, until then, if I have enemies to make, I will."

When I was finally convinced beyond any doubt that Joe was the murderer, I was faced with a dilemma. On one hand, I was getting some fantastic stories from talking to him and had built a good relationship with him. There was also the fact that the public appetite for Rachel stories was massive. Every time the murder appeared on the front page of the Herald, sales went through the roof. The amount of times Rachel's photograph was splashed on the front page of the paper became a bit of a running joke among journalists and ordinary members of the public.

At the same time, it was so obvious he was guilty it got to the stage where I could not keep talking to him in good faith.

Rachel O'Reilly was a young mother who had been brutally murdered and left a heartbroken family behind. I had met Jim and Rose Callaly on a few occasions and was always struck by how courteous and courageous they were, despite all they had been through.

I began the process of ending contact with Joe O'Reilly. In early November, a story appeared under the headline "Mum's killer made fatal mistakes . . . gardai focus on suspect, his mistress and key witnesses." I wrote that "detectives are playing a game of cat-and-mouse with the chief suspect who has finally realised that his supposed foolproof plan is falling apart. He is described as a psychopath who believed that he would not be caught. But he is having trouble sleeping now and is panicking as he realises that the net is closing in."

We had known Nikki Pelley was seeing Joe for some time and on 11 November we photographed Pelley as she went to her office in Dundrum. I contacted her on her mobile phone and told her I knew she was having an affair with Joe and asked her for a comment. She hung up on me and her phone was almost permanently turned off after that. Pelley appeared on the front page with her face blacked out and was described as "blonde lover of Rachel suspect". After that story I rang Joe but he told me he would not talk to me any more and hung up the phone.

Five days later, Pelley was arrested on suspicion of withholding information and Joe spoke to me again, saying: "I'm happy there have been arrests alright, but I have no further comment to make." I never spoke to him again but continued to follow the story.

Coverage was now dominated by talk of the "chief suspect" and it was obvious to everyone this was Joe. When Pelley and Derek Quearney were arrested, the headline in the Herald the following day was "Rachel: two arrested known to husband."

The media was all but saying Joe had killed Rachel. He was arrested the day after his lover and friend were detained.

I arrived into work at 6.30am and heard Joe was to be picked up about 35 minutes before it happened. We scrambled a photographer to The Naul and got a shot of Joe being led out by detectives in handcuffs.

We had awful trouble trying to convince our lawyers to let us use the photo showing Joe in cuffs, because there was a small danger it could prejudice any possible future trial.

We eventually got permission and the frontpage poster edition was one of the biggest-selling copies in years.

I spoke to Jim and Rose Callaly the day of Joe's arrest and Rachel's mother told me, "I'm just praying that we get justice for Rachel. I can say nothing else. It is a nightmare and I'm afraid to go to sleep at night for what I'll dream. I keep thinking that I will have my girl back. I can't describe it."

She was in tears as she spoke and my heart went out to the family because Joe was no longer allowing them see the children, Luke and Adam.

After Joe's arrest the net began to close in and he was eventually charged with Rachel's murder. I was surprised when this happened because some senior detectives didn't think there was enough evidence to convince the DPP that circumstantial evidence was sufficient to get a charge.

But it was and the sheer amount of circumstantial evidence left few people who observed the trial in any doubt that Joe O'Reilly killed Rachel. Now he has been found guilty and the Callalys have got justice for their daughter.

A pure psychopath I'd say I got to know Joe O'Reilly pretty well while we were in contact with each other. On one level, he seemed like a nice man. He could hold a conversation and was quite interesting . . . the sort of guy you could sit down with and have a few pints and a chat.

On the other hand, he is a pure psychopath. He has never shown a shred of guilt or remorse for leaving his two boys without a mother. I don't know why he killed Rachel and I don't think anyone else does either. If he did it because he wanted to have custody of Luke and Adam, he was misguided. He will not see his sons as a free man for at least 20 years.

Seeing Joe outside the court on the first day of his trial felt very strange. We walked past each other and exchanged glances but didn't speak. I was on the phone later that day and a colleague told me he was pointing me out to his legal team.

His barristers quoted Evening Herald stories several times in court and tried to say witnesses might have read information about what they were saying in the paper.

Anybody who blames the media for dealing with Joe O'Reilly and giving the story blanket coverage is naive. He dug his own hole by courting the press and brought about his own downfall. It is commonly said that today's newspapers are tomorrow's chip wrappers. That is true in most cases. The Rachel O'Reilly murder was different, and I don't think I'll see anything like it again in my professional career.

For a long time, I could not go a day without people asking me about Rachel and Joe, whether he did it and if he would be charged. The murder has captured the public's imagination like no other case in Irish history. I witnessed events up close and got to know some of the personalities involved.

Joe O'Reilly will now be in jail for life, Rachel O'Reilly is dead and her family will never recover from what happened on that awful day on 4 October 2004. Luke and Adam O'Reilly will now have to grow up without both their parents.