First, I'm so sorry you have to deal with this.

I'm not sure if this will help, but in my experience the understanding of Asperger's Syndrome is still somewhat low among medical professionals, and is likely lower in public service workers.

Because the syndrome is so new, the police might not understand that a 5 year old with AS is much more likely to tell the truth and a 5 year old NT.

I would encourage you to reach out for whatever support you can, including assessing whether the social workers, police, hospital workers, etc. really understand AS. Maybe look for a local support group for the Autism Spectrum, and solicit help from other parents.

http://www.autism-society.org/
Has a listing of local support groups

I wish you strength.