(US,idiomatic) With sufficient evidence to establish responsibility definitively.
1854 (published 1855, delivered 1854), Sherman B. Canfield, The Indications of a Divine Purpose to Make Our Country a Model Christian Republic: A Discourse Delivered on the Day of Annual Thanksgiving, November 30th, 1854, p. 26:
…and anon millions awoke, who had been blind, deaf, dead to rights, duties and interests of the highest moment.
Because of the video replay, the ref had him dead to rights on the penalty.