The use of genomic health and ancestry data, notably DNA data held by private companies, by law enforcement in criminal investigations raises important ethical issues and requires ethically informed regulation. The ethical issues in play include informed consent, ownership rights to genetic data (e.g. (potentially) joint moral rights), the moral right not to self-incriminate and the collective moral responsibility to assist law enforcement in legitimate criminal investigations. The articulation and justification of relevant moral principles can yield ethical guidelines that give direction to regulators in this under-regulated area.