MEMORANDUM *

Appellant Eugene Harris Corbett appeals the district court’s denial of his § 2254 habeas petition. We have jurisdiction pursuant to 28 U.S.C. § 2254, and we AFFIRM.

*866Corbett contends that he received ineffective assistance of counsel because his trial lawyer, Francis Akamine, failed to discover until the eve of trial information that would have supported the mitigating defense of Extreme Mental or Emotional Disturbance (“EMED”). As a result of this failure, Akamine did not present expert testimony in support of that defense. A successful EMED defense would have reduced Corbett’s offense from second degree murder to manslaughter.

The parties do not dispute that Aka-mine’s conduct fell outside the wide range of reasonable professional assistance required by Strickland v. Washington, 466 U.S. 668, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984). They do dispute whether that deficient performance prejudiced Corbett. Counsel presented enough evidence for the jury to find that Corbett acted under EMED, and the jury received an EMED instruction, which properly described the State’s burden of disproving EMED beyond a reasonable doubt. Although expert testimony might have raised such a doubt, here there has been no showing of what an expert actually would have testified. A proffer of such evidence may not always be necessary to support a finding of prejudice, but here the circumstances supporting an EMED defense were sufficiently questionable that we require more than pure speculation about the nature and substance of an expert’s testimony.

For these reasons, we AFFIRM the district court’s denial of Corbett’s petition.

AFFIRMED.