Mary Kelly found herself running through the streets, past anxious friends, past protesting police officers, past the cordon and on to the front door beyond which lay her son.

Then she stopped. Turning away from the doorstep, she fell to her knees and looked skywards. “Please, mum,” she prayed, “Take care of my Liam.” But it was too late for her 16-year-old son, the “gorgeous Liam, the man of the house, the protector of his brothers and sisters, the son who shone”.

He had been shot twice in the arm and heart at point-blank range in a dispute over £200. Three years later, and after the shooting of another youngster in Liverpool, Ms Kelly is still grieving and is still angry. Guns have permanently scarred her life and those of Liam’s siblings, Sika, 9, Kotsia, 14, Calum, 19, and Hayley, 25.

She said: “It’s destroyed us, and this family is still not able to cope. It’s like volcanoes are erupting all the time in our house. We just do not know how to deal with it. We can’t connect with each other any more. Before we would sit down and talk and chat. Now there’s just anger. A light has gone from us all.”

Before 1.30am on June 19, 2004 – when Liam became Liverpool’s youngest gun fatality, which he remained until Wednesday evening – Ms Kelly, 42, did not think that guns existed in her community. She had other worries for Liam. “Liam was always playing on motorbikes and I was always worrying that he would have an accident. Never did it cross my mind that he would be shot dead.”

On the night that he was killed, Ms Kelly had gone to bed shortly after 10pm thinking that Liam had gone to his girlfriend’s house.

The picture that emerged during the subsequent criminal trials was that the youngster had left his mother’s house to meet people to whom he had previously lent money.

As he stepped out of a car driven by his friend Nicola Sorrell in Grafton Street, Dingle, soon after 1am, he was shot by a masked man with a double-barrelled shotgun. He staggered to a nearby house while the police were called.

Ms Kelly said that she was awoken by Calum running into her room screaming that Liam had been shot. She said that everything that followed that night, and in the years thereafter, was a haze.

“I did not even know where Grafton Street was. I know I was driven there and then saw the police. The policemen were trying to stop me going over the cordon but I got to the front door. Then I just could not go in. It felt like somebody had taken me over. My mother had died the previous year and I believe it was her that stopped me going in. I just remember going to my knees and asking my mum to take care of him.” Soon afterwards the police told her that Liam had died.

What has made Ms Kelly’s anger more potent, and the aftermath harder, is knowing that all the suspects in her son’s death have not yet been brought to trial. Just one man, Anthony Campbell, then 19, has been found guilty of murder. He was sentenced to 23 years’ imprisonment two years after Liam’s death.

Another man, Peter Sinclair, 26, pleaded guilty to assisting a man who was allegedly involved in the killing of the 16-year-old while Hannah Morgan admitted perverting the course of justice by giving a false witness statement. Another man, Patrick Smeda, 23, was acquitted in June of luring Liam through a series of phone calls to the street where he was shot.

Despite an appeal on Crimewatch, the man Sinclair and Morgan admitted conspiring to assist has still not been traced by police. Kevin Thomas Parle, 26, is believed to be abroad.

Ms Kelly said: “These people will one day be free while my son has been taken away from his family for ever. How can I move on?”

She added: “I do not go outside my house now. I am scared of coming face to face with his killer’s family. I can’t bring myself to go to his grave - it just does not feel real. I hear a knock on the door and think to myself, ‘That sounds like Liam’s knock’.”

Ms Kelly, who made a public appeal after Wednesday’s shooting of Rhys for an end to the “senseless killing”, added: “My heart goes out to Rhys’s mum. Her life and world are no more and will never be. They have totally, totally destroyed her.”

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