Care worker Daniel Seggie stabbed his father 60 times and struck him with a hammer 20 times at the home they shared.
Just 24 hours after the rampage, he was seen enjoying a McDonald’s.
Over the course of the next week, Seggie withdrew money from his dad’s bank account before leading the police on a chase across three countries.
Detectives said the evidence showed Geoff, 59, was alive and struggling for at least part of the brutal assault that took place in his own bedroom.
Seggie was sentenced to life in prison with a minimum term of 20 years.
Despite the brutality of his crime, mum-of-two Zoe Spence stands by him.
She said: “Dan, I’ll still always stick up for. He was always the guy that never did anything wrong to me.
“He always supported me. He always had my back and the kids.
“It still seems unbelievable, but obviously the evidence is there. He’s been sentenced and he’s gotta do his time.
“But I try and forget about that and just try and think about the good Dan and the good times we had and try and blank that bit out.
“It’s still a massive shock even a year down the line. People ask me about him and I’m still there defending the guy.”
Zoe thought that Daniel, 31, was the man of her dreams.
But, out of the blue, she was plunged into a manhunt as he sent her a series of haunting texts about his crime.
In an interview on true-crime series What The Killer Did Next, she said: “He sent me a message saying he was on the way, and then just didn’t turn up.
“I thought he was obviously busy or something’s come up with work.
“I tried ringing him numerous times and just got nothing. I was worried.”
Zoe headed to Daniel and Geoff’s home in Mackworth, Derbys, and found it over-run by police.
Geoff’s body had been found with stab wounds to the neck, chest and head.
Seggie had stayed at the home for two days after the murder, even ordering his usual takeaway and visiting a McDonald’s as his dad’s body lay in the bedroom.
He used his father’s phone to impersonate him and then went on the run for seven days as he travelled to Cardiff and then Glasgow.
After a few days Seggie sent Zoe a message that said: “I’m sorry. I honestly don’t know what’s happening. My heart is broken, but also my mind.
“I have no idea what has happened this past week. It’s like I’ve been asleep for a week and woken up in a nightmare.”
In another message he told her: “I’m so sorry. I’m somewhere north. I wish I was okay, but I’m tired and alone, and I feel so confused. I don’t want you to worry. I will be okay, and I love you.”
Zoe tried to help police by convincing Seggie to reveal his location. She said: “I think Dan was scared, and panicked. I think Dan knew he was gonna get found out. He left a lot of evidence behind.”
In a 3am text he finally revealed he was staying at a hotel in Glasgow and shortly after that he was arrested.
Zoe continued: “I thought Dan was innocent. I thought it was all mistaken, and I didn’t know what was going off, VICTIM: Dad so I just presumed they would question Dan and then he’d be walking out and it would all be a dream.”
In May 2017, Seggie was jailed for murder after pleading guilty – but he offered no explanation.
Zoe said: “When I saw Dan in court he was a completely different person. This is when I started thinking maybe there is more to this than what he was letting on and the Dan I knew, because there was just no remorse.
“He was just in the box, come straight in. He didn’t even acknowledge his family, or myself, my sister, all his friends. He just turned away.”
Sentencing him, Judge Dickinson told Seggie: “It was a savage and merciless attack.
“Your father suffered. He had defence injuries that show he tried to fight or fend you off for some time.”
What The Killer Did Next continues tomorrow at 9pm on Crime + Investigation (Sky 156, Virgin 275, BT 328 and TalkTalk 328) with episodes available on catch-up services.