"He was great for his hugs, and his smile lit up the room."
Kristina Cassidy says a lot of people loved her 18-year-old son, Caoimhin. When you talk to those who knew him, the words "affectionate" and "lovable" are often mentioned.
But he was found dead in a burnt-out car in Londonderry in June 2019.
Since then, his family has struggled to find out what happened to a much loved son and grandson.
Caoimhin's story is told in 'Assume Nothing: The Boy in the Burning Car', a new podcast from BBC Northern Ireland on BBC Sounds.
In many ways, Caoimhin was a typical teenager. He followed Liverpool Football Club and loved rave music.
He liked canoeing and rock-climbing and hoped to become an outdoor education instructor.
But Caoimhin did not lead a carefree life.
When he was a toddler, his mother suffered a period of ill health, and from then on, Caoimhin was raised by his grandmother.
At four years old, he was diagnosed with ADHD and he struggled with education. By the time he was a teenager, he rarely attended class.
His great uncle, Charles 'Nucker' Tierney, was worried about him.
"He was doing things he shouldn't have been doing. When he was younger, he'd be breaking things over at the shops. Eventually he went into drugs and was doing things that were stupid".
His family says he lived under paramilitary threat from the age of 14, and was effectively banished from his home city of Derry.
"That made Caoimhin want to go on drugs, because he was getting death threats," says his aunt Danielle Cassidy.
"Big boys giving 15-year-olds death threats. It didn't help him, did it? It made him worse, more than anything".
When he was 18, Caoimhin ended up in a young offenders' detention centre. It affected him profoundly.
"He cried on the phone," says his mother, Kristina.
"After the young offenders' centre, that's when he really slowed down. He promised me and his nanny he would never be back in jail again".
Two men 'ran from the scene'
In May 2019, Caoimhin went to a local youth worker for help and tried to quit using drugs. He was due to start a training programme that could lead to him becoming an outdoor pursuits instructor.
But then tragedy struck.
Caoimhin lost his life in the early hours of 1 June 2019.
His body was found in a burnt-out stolen car in the Galliagh area. The vehicle had crashed into a lamp-post and caught fire a short time later.
A post-mortem examination later revealed Caoimhin had not been seriously injured in the crash, but died after the car caught fire.
Police who attended the scene describe the incident as one of the most harrowing they had ever encountered.
The Cassidy family speak about living with the burden of grief and unanswered questions.
"People ask me still to this day, how am I?" says Kristina.
"I don't know. That's my answer, I don't know.
"Caoimhin's death isn't getting any easier for me. It will never be easy for me".
PSNI Det Insp Michael Winters is leading the investigation into Caoimhin's death.
He says the possibility that he was deliberately harmed has never been ruled out.
"I can't say, sitting here today, that Caoimhin wasn't murdered. I just can't say that".
From the outset, the police suspected the involvement of other people for a number of reasons.
Caoimhin was found in the front passenger seat. CCTV footage indicates the presence of other people in the vehicle.
Police say a forensic report confirmed the car was set alight inside from the passenger compartment.
A lighter and two mobile phones were discovered in the vehicle, although they were significantly damaged by the flames.
"You might suppose that's the reason the vehicle has been set on fire, to destroy evidence, that's one line of inquiry," says Det Insp Winters.
"We can't rule out it was destroyed as a deliberate act to harm Caoimhin, but it is common practice for stolen vehicles to be burned to destroy evidence".
Police believe the teenager had been at a party in the Creggan area, but witnesses say he left alone, about 01:30 BST, with the intention of stealing a car.
About 03:30, a red Mazda 6 was reported stolen from Oakfield Avenue.
Police then observed the car in various locations in the city and crossing the border into the Republic of Ireland.
Det Insp Winters believes other people got into the car at some point, but he doesn't know for definite who they are or what their intentions were. However, he believes Caoimhin may have known them.
The Cassidy family is still searching for answers.
"I want to face these people and let them see what it has done to me and my family," says Kristina.
'All I can do is cry'
She says her mother, Margaret, barely leaves the house anymore and often sits crying in the kitchen.
"He's in my heart, morning, noon and night. All I can do is cry," she told the BBC.
She prays that someone will bring them information about the people in the car.
"Please, if anyone out there knows anything about them, please I beg you, give my broken-hearted family the information".