It means what you say can be published and attributed to you by name, unless you agree otherwise before saying it.
Yes. Families and witnesses can decline questions, pause or stop at any time, and off-record terms are agreed before speaking.
Most interviews last between forty-five and ninety minutes, and they can be conducted remotely if that is easier for the family.
Quotations are checked against the recording, facts are compared with documents where possible and unsupported claims are labeled or removed.
Contact the newsroom with the person's name, the investigating agency and the main records you hold, and the request will be read.