Detectives investigating the murder of 14-year-old Jaden Moodie say they have recovered a car believed to be involved in the incident that led to his death.

The black Mercedes B-Class was recovered in the Carlisle Road area of Leyton on Wednesday afternoon in what police said was a “significant development in our inquiries”.

DCI Chris Soole, from the homicide and major crime command who leads the investigation, said: “We are treating the recovery of the car as a significant development in our inquiries, which are still very much in their early stages.

“Jaden’s family are being fully supported and kept updated by our team. This is a truly heartbreaking time for them and we are doing everything we can to find out who was responsible for Jaden’s death.

“I would urge anyone who has information about those responsible but who has not yet made contact with police to do so straight away.”

Jaden who was attacked in Leyton in the east London borough of Waltham Forest, was described by friends and family as a “good, loving child” and moved from Nottingham to London within the last year. His death stands out among the rising homicide rate because he is the youngest victim in London for over a year and because of the brazenness of the attack.

Homicide detectives are keeping an open mind about the motive but multiple sources said a significant line of inquiry was that the attackers were involved in drug dealing in London and beyond in so-called “county lines” operations.

Jaden was struck by a black Mercedes car at about 6.30pm on Tuesday evening, suffering stab wounds so severe that within 40 minutes he was pronounced dead at the scene.

Police say they believe three men got out of the car and stabbed Jaden repeatedly before driving off, leaving the boy mortally wounded on the ground. The car is thought to have been a black Mercedes B-Class with extensive frontal damage.

It was clear that police were shocked by the nature of the attack and that a child so young could be the victim of such a level of planned violence. They hope community disgust will lead to information identifying the killers.

Ch Supt Richard Tucker said the murder had left him unable to sleep: “The age of the victim – a boy aged 14 – beggars belief and I completely understand the alarm and concern it has raised from those who live and work in the area.

“A lot of people are saying he was a young man. He wasn’t. He was a boy,” said Tucker. “It’s shocking. It’s an appalling event. And this will affect huge numbers of people.”

Facebook Twitter Pinterest Flowers have been placed near where the 14-year-old was stabbed to death. Photograph: John Stillwell/PA

The scene of the attack at Bickley Road remained cordoned off on Wednesday morning, with a small pile of flowers beginning to grow at one end.

Soole said: “Everything we know so far points to the fact that this appears to be a targeted attack and those who carried it out had only one objective, which was to inflict fatal injuries on Jaden.

“We continue to investigate why Jaden was singled out and retain an open mind at this time. My team is working tirelessly to apprehend those responsible for this cowardly attack.”

Writing on Facebook, Josh Grant, who said he was the victim’s uncle, said: “Rip to my little nephew, stabbed 7 times today in London. Can’t believe I’m never gonna see you again. Uncle Josh will never forget you.”

He wrote that the family had moved to London from Arnold in Nottingham six months ago and that he had warned his nephew to behave. “[He] didn’t listen. He looked up to me so much. I tried to show the right way. I feel so shit and upset right now.”

Speaking at the scene in Leyton, Solomon, who would not give his second name, said he had previously been in a relationship with Jaden’s grandmother and that the boy was “a good, loving child” who was “sensible and knowledgable”.

The factors driving such violence are being urgently studied as the homicide rate rises and drug markets change.

A council-commissioned report in Waltham Forest, which looked at youth violence and gangs, found that poverty and the drug trade were key factors. It found that younger children were being recruited as drug runners, and some aged 12-17 were said to be increasingly involved in serious violence, both as victims and perpetrators.

The gangs were driven increasingly by profits from the illegal drug market, rather than postcode rivalries and protecting territory, the study by academics at London South Bank University found.

The report found that gangs in the area were grooming children as young as 10, sometimes persuading them to commit a petty crime such as shoplifting as a means of normalising criminal behaviour.

Clare Coghill, the leader of Waltham Forest council, said poverty had left young people vulnerable to being drawn into gang activity. Speaking about the report’s findings, she said: “These kids are not doing this to get cars and trainers. They are doing this to eat and have a sense of social belonging.”

Crime is an issue that worries locals. A close family friend, who did not want to be named, said: “My sister and I drove down [Bickley Road] 15 minutes before it happened. I can’t believe it. We’re going to keep having this conversation until people do something about it. They should have cameras on all these roads because they know these are the hot roads where things are happening.

“My brothers were just asking my mum if we can move because it’s really bad here. My brother has been targeted before. He got jumped out on and he doesn’t even know who these people are. It was probably a case of mistaken identity. He had to run home. It’s just not safe.”

Jaden is believed to be the youngest murder victim in London since 14-year-old Corey Junior Davis was shot dead in Forest Gate in September 2017. There were 134 homicides in 2018, the highest since 2008.

On Tuesday night witnesses described how the 14-year-old was knocked off his motor scooter – which threw his helmet 10 metres away – before his attackers stabbed him, including in the back.

Jaden’s killing is one of three violent incidents in five days in Leyton. On Wednesday afternoon a man is thought to have been injured in an attack on Bromley Street, three streets down from where Jaden was killed the previous evening. On Saturday a woman in her 30s was stabbed on Church Street, a short walk away. Police said there was nothing to suggest that the incidents were linked at this stage.

Police said a section 60 order was in place, which allows officers to stop and search people within a defined area without needs for reasonable grounds and in order to prevent and deter further violence.