Kamil Pustkowski (17) from Limerick, one of five teenagers killed in the M9 wrong-way crash in Co Kildare last weekend, was recently diagnosed with autism. He was described by a source as “impulsive and easily led”.One person who had dealings with him said he appeared to be “doing better recently”. But another insisted his offending was rapidly escalating.“He was the kind of young lad who was only going to stop if he killed somebody or was killed himself,” that person said.The same source said Pustkowski had rapidly attained a degree of notoriety among his peers because he so frequently posted content of himself in stolen cars. This included being pursued by gardaí and also engaging in wrong-way driving on motorways, involving near misses with oncoming traffic.“He’d almost always show his face in the car,” said one source of Pustkowski. He later shared that footage on the online video sharing platform TikTok, where he had multiple accounts.Gardaí were so concerned at the frequency and brazenness of his offending that his name was even cropping up in policing conversations about tackling joyriding nationally.Pustkowski was on bail at the time of his death last Sunday at about 3am near Moone, Co Kildare, having been charged with joyriding-related offences. [ M9 crash: What happened when? From attempted break-ins to the fatal collisionOpens in new window ]A ban on leaving Limerick was one of the conditions imposed on him before his next scheduled court appearance in September.Despite being restricted to Limerick, he often travelled to places such as Carlow, Kildare and Dublin – and as far as Monaghan – to “go on the tear in cars” with others, as one source put it.“Like them all, he knew [gardaí] wouldn’t follow him the wrong way down a motorway,” said one garda. As a result, once he was being pursued by gardaí, there followed a “frantic, crazy” dash to what he saw as the safety of the nearest motorway.Despite the reputation Pustkowski had gained, especially since the start of this year, he was also the victim of violent bullying. A video, seen by The Irish Times, apparently recorded recently, shows him being kicked and punched by a group of similarly-aged boys.He tries to move away from them before collapsing on the ground. He is crying and pleading for the beating to stop. Due to his engagement with the criminal justice system, he was receiving support from Extern, an organisation specialising in “positive change through youth justice” and was engaged in a full-time manufacturing course.The four others killed on the M9 at Moone, Co Kildare, in the black BMW last weekend were: Jack Kennedy (17) from Athy, Co Kildare; Jeremy O’Brien (18) from Carlow; Joe “Joey” Carthy (15) from Athy; and Alex McCarthy (17) from Carlow.The BMW they were in was not registered to any of the teenagers or their families, but it was not stolen. It is believed to have been purchased for just over €1,000 early last week.Pustkowski and Kennedy, from the Green Hills area of Athy, were regarded as the most dominant of the five young males killed last weekend.Kennedy is described as having had “an awful life” and “pushed from pillar to post in care”. He attended Ardscoil na Tríonóide in Athy and was in a residential placement in the care of child and family care agency Tusla.In July, Kennedy was among a group of young males in a Ford Ranger that was driven over a motorcyclist in Graiguecullen, Co Carlow, after it had been stolen in Rathcoole, Co Dublin, hours earlier.The Ford Ranger, a large 4x4 utility vehicle costing up to €72,000 new and weighing about two tonnes, was driven on to the narrow roads of Graiguecullen just after 7.30am on Wednesday, July 8th, with a patrol car in pursuit.When the Ranger ran into traffic, the Garda car pulled alongside, only to be rammed from the side. The Ranger was then driven up on to the pavement, to undertake the line of traffic ahead, hitting the car in front. It knocked over the motorcyclist, driving over him and his motorbike.The vehicle sped away over traffic calming ramps, with footage of the incident going viral on social media. It was soon abandoned, with four suspects, including Kennedy, arrested on foot a short distance away.The motorcyclist suffered serious head injuries and, as a result, went blind for a time. Sources said he suffered a severe skull injury, causing a swollen brain and gravely endangering his life.Gardaí were waiting the results of forensic tests on the Ranger before they could link Kennedy and the other suspects to the vehicle for the purposes of charging them with a crime.[ Kathy Sheridan: Grown-ups had a role to play in dangerous actions by childrenOpens in new window ]Alex McCarthy (16) was also questioned by gardaí about the incident last month in Carlow. It was strongly suspected he was one of the four males in the Ford Ranger.He was from a settled Traveller family. He attended St Joseph’s National School in Carlow town where one teacher remembers him as a “fine boy – no trouble at all”. He went on to Tyndall College secondary school, but left before completing his Junior Cycle exams. He is understood to have loved horses and enjoyed sulky racing – a common pastime among some Travellers.Joe ‘Joey’ Carthy (15) was from a settled Traveller family in Athy. He lived in the Clonmullion estate, a working class area in the northeast of the town, with his siblings and parents.He was a member of St Michael’s Boxing Club from the age of 10, where his father is a long-time volunteer. His mother is understood to have taken in foster children. The funeral of Joey Carthy at St Michael the Archangel Church in Athy, Co Kildare, on Friday. Photograph: Colin Keegan/Collins