Tragic cases like the deaths of Fiona Pilkington and her daughter could be repeated because police officers are too embarrassed to ask victims of crime if they are disabled, inspectors have warned.
Disabled people told a joint review of disability hate crime that the police service had become "too sensitive about causing offence".
Officers and control-room staff as a result are reluctant to ask victims if they are disabled, the inspection of police, probation and Crown Prosecution Service found.
In addition, confusion over how to define disability hate crime means it is not as easily identified as racist or religiously-motivated attacks.
The joint inspection was prompted by the case of Ms Pilkington, who killed herself and her disabled daughter Francecca Hardwick in 2007 following 10 years of sustained abuse.
Asked if such a case could be repeated in light of its findings, Steve Ashley, programme director to HM Inspectorate Constabulary (HMIC), said: "Yes, it could."
He said: "Police officers don't like to say to people 'are you disabled?' So even in cases where they have in their mind that the person may be suffering from a disability they just seem to be embarrassed about actually asking the question."
He added that forces had to "get police officers over this embarrassment factor about asking questions".
The HMIC, HM Crown Prosecution Service Inspectorate (HMCPSI) and HM Inspectorate of Probation (HMIP) review found victims of disability hate crime are being let down by the criminal justice system.
The immediate priority should be to encourage more people to come forward to report disability hate crime as under-reporting remains a significant concern, the report said.
A total of 1,744 disability hate crimes were recorded by the police in England and Wales in 2011/2012.
The review also calls for police to ensure every opportunity is being taken to identify victims of disability hate crime.
Mr Ashley went on: "There's a lack of willingness by police officers and police staff in control rooms to ask the right of questions to establish whether it's a crime, whether its anti-social behaviour and what effect disability is having on that person in terms of the effect on the crime.
"There's no doubt that understanding of the definition is a major issue for the police. It's disappointing they've not moved further forward."
He added: "Clearly, it is a confusing issue. It's not as easy as identifying a religiously-motivated attack or a racially-motivated attack. It isn't that easy."
Inspectors visited six police forces and the CPS and probation trust offices based at Cleveland, Cumbria, Derbyshire, Hertfordshire, Greater Manchester and West Midlands.
They also interviewed representatives from witness care units, the witness service, victim support and a number of independent disability advocates.
The report recommends that the police, CPS and probation trusts should adopt and publish a "single, clear and uncomplicated" definition of a disability hate crime.
In addition, the three agencies should consider how their front-line staff participate in disability hate crime training.
The CPS should put regular checks in place to ensure the accuracy of all data relating to disability hate crime, the report said, while probation trusts should tackle the issue among known offenders.
It will also recommend that the Law Commission, the body that deals with law reform, looks at creating a stand-alone offence for dealing with disability hate crime.
Chief inspector of the CPS Michael Fuller said: "It would help with the awareness of practitioners because they would have a specific offence to work to and it would help in terms of victims in terms that they feel their concerns and the experiences they've suffered can be taken more seriously by the authority."
The case of David Askew, who had severe learning disabilities and died after decades of torment by yobs outside his house in Hattersley, east Manchester, was also cited.
Victim Support chief executive Javed Khan said: "We know that whilst some police forge excellent relationships of trust with victims who have disabilities, this is by no means a standard across all areas.
"Police must change to ensure they deliver improved services to victims of disability crime, with victims encouraged to report such crimes in the first place.
"Police forces in particular should work with charities and previous victims of disability hate crime, who can help build officers' understanding and confidence. This will help to improve how officers work with disabled victims on the frontline."