Background: A number of jurisdictions have instituted legislation requiring an independent person to be present during police interviews with vulnerable people. In Victoria, Australia, a group of volunteers known as Independent Third Persons help to fulfil this role with people who present with cognitive impairment arising from their mental illness or disability. This study sought to explore the perspectives of the Independent Third Person volunteers on police identification of and responses to people with intellectual disability (ID). Methods: All registered Independent Third Person volunteers across the State of Victoria in Australia were identified and sent a postal survey on their experiences and confidence in performing their role, their perceptions of police competency, and the challenges they faced working at this interface. Results: Of the 207 Independent Third Persons identified, 94 (45%) completed and returned the survey. Participants reported that despite being overly reliant on previous police contacts and cues relating to communication difficulties, they viewed police as generally competent in their ability to identify people with ID. They also considered themselves confident in performing their own roles at this interface, albeit more so at the perfunctory aspects of the role and less so with the emotional aspects of supporting the person being interviewed. Conclusions: Police are seen as competent at identifying those with cognitive deficits and seeking appropriate supports for the person with ID in the interview context. More specialised training for police members is recommended in communicating with people with IDs. Volunteers working at this interface require additional support and training in helping to meet the emotional needs of those being interviewed. (Contains 6 tables.)