A gang would often pelt the family's house with eggs and stones
A coroner said the deaths of a mother and daughter after years of bullying could have been prevented if the authorities had taken them seriously.
Fiona Pilkington, 38, of Barwell, Leicestershire, set fire to her car as she and her daughter sat inside.
An inquest heard police ignored reports of abuse over several years.
A jury heard failings by police and councils meant Ms Piklington was never assessed by social workers, though they were aware she had "suicidal thoughts".
Following the deaths of Fiona and her 18-year-old daughter Francecca Hardwick, who had severe learning difficulties, Leicestershire County Council began a serious case review.
It found Leicestershire County Council, Hinckley and Bosworth Borough Council and Leicestershire Police failed to share information about the family, their disabilities and the abuse they were receiving from a 16-strong gang of youths.
Coroner Olivia Davison, at the Loughborough inquest, said: "If somebody had sat this woman down with a cup of tea they could have perhaps helped her.
"You need to sit down with people to get information from them and I wonder why that wasn't something that occurred here."
The review made five recommendations, including to investigate the impact of anti-social behaviour on people's lives, share information between authorities and "read the situation from the victims' point of view".
Mick Connell, director of adult services at the county council, said: "The first issue is that Fiona had suicidal thoughts and that was not taken in its entirety with the events of anti-social behaviour.
"There should have been an assessment by a social worker and then a safeguarding investigation where we would have looked at the circumstances as they presented."
Tony Howlett, the county council's service manager for people with learning disabilities, added: "It was seen as more of a general expression of her anxieties at the bullying and not any sort of intention to commit suicide."
He told the inquest no extra support of counselling was offered to the family during stressful times.
Despite police logging 33 calls regarding the family, no-one was ever prosecuted for bullying Ms Pilkington, Francecca and her brother Anthony, now 19, who is severely dyslexic.
Pelted with stones
The pair's bodies were found in the family's blue Austin Maestro at the side of the A47 near their home on 23 October, 2007.
Weeks after the deaths an injunction was taken out against a "problem family", who cannot be identified, to protect other victims.
The legal step was taken after attempts by police to control the family failed and the parents "refused to accept that their children had done anything wrong," the inquest was told.
Statements documenting 18 months of abuse and bullying were given to Hinckley and Bosworth Borough Council on 22 October, 2007 - a day before Ms Pilkington and her daughter died - in a bid to stop the family's behaviour.
The inquest earlier heard a gang would often pelt Ms Pilkington's house with eggs and stones and Anthony was attacked with an iron bar and locked in a shed at knifepoint.
The jury will return on Monday when it is expected to retire to consider its verdict.