What Is a Writ of Coram Nobis ?
The writ of coram nobis is available to a person who seeks relief from a conviction the sentence for which has already been served. See Heimermann, 205 Wis. 2d at 381-84.
A coram nobis petition is not barred by the decision in State v. Escalona-Naranjo, 185 Wis. 2d 169, 517 N.W.2d 157 (1994), because that decision relied on an interpretation of Wis. Stat. 974.06, and is therefore limited to relief sought under that section. See Heimermann, 205 Wis. 2d at 384-86.
Review of a coram nobis petition has an additional component not present in ordinary postconviction review: "The factual error that the petitioner wishes to correct must be crucial to the ultimate judgment and the factual finding to which the alleged factual error is directed must not have been previously visited or 'passed on' by the trial court." 205 Wis. 2d at 384.
And, as the foregoing suggests, the writ is "of very limited scope," being aimed at the correction of "an error of fact not appearing on the record." See Jessen v. State, 95 Wis. 2d 207, 213-14, 290 N.W.2d 685 (1980).
Coram nobis is not available "to correct errors of law and of fact appearing on the record," because those errors are reachable by way of "appeals and writs of error." See id. at 214.