This week, Stuart Hazell - the man she called Grandad - was sentenced to life in prison after admitting killing her.
In their first in-depth television interview, Tia's mother and grandmother speak to the Tonight programme on ITV at 7.30pm.
During the nine months since Tia disappeared former Detective Mark Williams-Thomas followed the story, spending time with her grieving family and witnessing the impact on a community of such a terrible crime.
On the day before she vanished Tia had asked her mum if she could spend the weekend at her grandmother Christine’s house. Her step-grandfather Stuart would be there and she loved spending time with him.
Tia met up with Stuart Hazell in Croydon that Thursday afternoon - they were seen together on CCTV, the last images of Tia alive. The next day her family reported her missing.
Five days later, as the press descended on the family home, Mark Williams-Thomas received a call from Stuart Hazell. He wanted to appeal for Tia to come home and protest his innocence.
Do you know what I mean? I’d love to sit there, and they ask me stupid questions, like yesterday oh ‘did you do anything?’ Well no I f** didn’t! Excuse my language. But, no I didn’t. I’d never think of that, I loved her to bits. She was like me own daughter. For God’s sake, we had that sort of relationship; she wanted it she got it.
By this time the police had already searched the house twice, had viewed 800 hours of CCTV but found nothing – Tia had vanished and Hazell was playing the distraught family member. But why had Stuart Hazell, knowing that Tia’s body was in the house, knowing he had killed her invited cameras in to speak to the nation?
Forensic psychologist Kerry Daynes reviewed the interview and gave her opinion.
During the interview he’s very keen to get across the fact that he feels trapped in his own home. And I am sure he does feel trapped because he has got Tia’s body in the attic...and she is decomposing and really there is only two choices available to him at that time, he has either got to move Tia from the house or he has got to remove himself from the house.
As suspicions over the part Hazell played in Tia’s disappearance intensified - the family closed ranks - believing him to be innocent. But their unwavering support of him opened them up to public scrutiny and stories began to appear in the papers questioning the welfare and happiness of Tia – adding to the families torment.
Two days after Hazell appealed for Tia to come home, Christine’s house was searched for a third time – after seven days and two previous searches, they discovered Tia’s body wrapped in sheets in a suitcase in the loft.
Tia’s mum Natalie speaks of the moment she was told by officers they’d found her daughter.
They took me into the dining room of my friend’s house, and that was then when they dropped the bombshell. And I remember looking up and all I could see was kids, just everyone’s kids and I just…I hit the floor. And when I looked up everybody was looking at me and it was just - their eyes told me I was in a nightmare.
Hazell disappeared and a warrant was issued for his arrest. Shortly afterwards he was picked up by officers on a nearby common. This was the moment the family realised they had been betrayed. Christine says she found it hard to believe the man she loved was a killer.
I believed she was in one of the safest places with one of the safest people that would protect her. I didn’t knowingly live with a killer – I knowingly lived with a man I loved with all my heart.”
Several months later, as the trial came closer, the family hoped Hazell would plead guilty to save them the pain of sitting in court to hear harrowing evidence of what happened to Tia. But when it began Hazell, charged with murder and sexual assault, pleaded not guilty and Tia’s family were faced with graphic details and images of her in court.
After four days of evidence, Hazell dramatically changed his plea to guilty. He was sentenced to life in prison and ordered to serve a minimum of 38 years.
But for mum Natalie, no sentence will ever be enough for the loss of Tia.
He doesn’t deserve to walk on that path, that pavement. Doesn’t even deserve to be in jail but he doesn’t deserve to die. He deserves to suffer.
Tonight: Living With a Killer is on ITV at 7.30pm