Noun
an unknown or fictitious party to legal proceedings
Source: WordNetThese were then replaced by the fictional characters John Doe and Richard Roe. Source: Internet
This usage is mocked in the 1834 English song "John Doe and Richard Roe": Two giants live in Britain's land, John Doe and Richard Roe, Who always travel hand in hand, John Doe and Richard Roe. Source: Internet
All five, along with Richard Roe and Sarah Moe, were charged under Penal Code §182, the conspiracy statute. Source: Internet