(dissenting in part).
I. The court remands this case for further proceedings on a claim which it finds was asserted for the first time on appeal. This is contrary to our general rule, previously applied in postconviction actions, that issues not presented in the trial court cannot be raised for the first time on appeal. State v. Lemburg, 257 N.W.2d 39, 46 (Iowa 1977). However, I would reverse and remand the case for new trial on the ground of trial court error in overruling Stanford’s motion to reopen.
II. Stanford alleged in the postconviction court and on appeal that the trial court erred in overruling his motion at the conclusion of the evidence to reopen the case to permit him to pursue and present testimony regarding Nabors’ alleged participation in “framing” innocent persons on drug charges in Michigan. The motion was based on due process grounds as well as principles governing newly-discovered evidence.
As the court acknowledges, a defendant has a federal constitutional due process right to present extrinsic testimony to establish bias of a witness in circumstances like those in this case. This was the holding in Johnson v. Brewer, 521 F.2d 556 (8 Cir. 1975), an analogous case in which Nabors was also involved.
This court distinguishes Johnson on the ground the offer of proof was adequate in that case but inadequate in this one. However, when the motion to reopen was made at trial in the present case, the trial court, Engelkes, J., based its ruling on the ground that the evidence, if produced, would be inadmissible. On this basis, Stanford’s request to develop additional evidence to supplement his offer of proof was denied.
The postconviction court, presided over by the same judge, confirmed this in the present proceeding, saying it had received the newspaper article as an offer of proof and acknowledging that “if the defense were permitted to bring witnesses before the court who knew the facts concerning the matters related in the newspaper article, they would undoubtedly testify substantially in accordance with what the newspaper article reflected.” A defendant *37cannot be denied relief for failure to make a sufficient offer of proof when the trial court has refused him that opportunity. Parrish v. Denato, 262 N.W.2d 281, 286 (Iowa 1978). I do not believe the trial court’s ruling on the motion to reopen can be sustained on the ground of inadequacy of the offer of proof.
Nor do I believe the reasons actually given by the trial court at the time are tenable. The holding in Johnson establishes the admissibility of the evidence. Judge En-gelkes, who presided at the Johnson trial after Stanford was tried, did not have the benefit of the Johnson decision at the time of Stanford’s trial, but this does not make the holding any less applicable.
The judge did have the benefit of Johnson at the time of the posteonviction proceeding and sought to distinguish it upon two grounds. One is the fact Stanford had not laid a foundation during the trial for impeachment of Nabors on this basis. As admitted by the judge in his postconviction ruling, this would have been difficult since Stanford’s attorney did not learn of the evidence until after the parties had rested. Presumably, if Stanford’s motion to reopen had been sustained, he could have been given the opportunity and burden to lay the necessary foundation. The other ground asserted by the postconviction court is also unsound. It is the alleged immateriality of the evidence. As observed by this court in today’s opinion, the materiality of the evidence is established by the federal court’s holding in Johnson.
I would hold that the postconviction court erred in refusing to order a new trial based upon the trial court’s error in overruling Stanford’s motion to reopen.