On March 22, 1993, two men driving through Anchorage, Alaska, solicited sex from a female prostitute, K.G. When K.G. demanded payment in advance, the two men pulled out a gun and forced her to perform fellatio on the driver while the passenger penetrated her vaginally, using a blue condom she had brought. The passenger then ordered K.G. out of the car and told her to lie face-down in the snow. She refused, and the two men choked her and beat her with the gun. When K.G. tried to flee, the passenger beat her with a wooden ax handle and shot her in the head while she lay on the ground. They kicked some snow on top of her and left her for dead. K.G. did not die; the bullet had only grazed her head. She flagged down a passing car to take her home. The police recovered a spent shell casing, the ax handle, some of K.G.'s clothing stained with blood, and the blue condom. About a week later, two military police officers pulled over Dexter Jackson for flashing his headlights at another vehicle. They discovered a gun (which matched the shell casing), as well as several items K.G. had been carrying the night of the attack. The car also matched the description K.G. had given to the police. Jackson admitted that he had been the driver during the rape and assault, and told the police that Osborne (D) had been his passenger. K.G. picked out D's photograph (with some uncertainty) and at trial, she identified D as her attacker. Other witnesses testified that shortly before the crime, D had called Jackson from an arcade, and then driven off with him. An ax handle similar to the one at the scene of the crime was found in D's room on the military base where he lived. The State performed DQ Alpha testing which cannot narrow the perpetrator down to less than 5% of the population. The semen found on the condom had a genotype that matched a blood sample taken from D, but not ones from Jackson, K. G., or a third suspect named James Hunter. D is black, and approximately 16% of black individuals have such a genotype. The testing ruled out Jackson and Hunter as possible sources of the semen, and also ruled out over 80% of other black individuals. State witnesses attested to pubic hair evidence found at the crime was also similar to Osborne's. D and Jackson were convicted of kidnapping, assault, and sexual assault. D sought postconviction relief and claimed that he had asked his attorney to seek more discriminating restriction-fragment-length-polymorphism (RFLP) DNA testing during trial, and argued that she was constitutionally ineffective for not doing so. The attorney planned to mount a defense of mistaken identity, and thought that the imprecision of the DQ Alpha test gave her '`very good numbers in a mistaken identity, cross-racial identification case, where the victim was in the dark and had bad eyesight.'' A more advanced . . . DNA test would have served to prove that D committed the alleged crimes. D sought the DNA testing that his attorney had failed to perform. The state courts concluded that D had no right to the RFLP test. In federal court, D claimed that the Due Process Clause and other constitutional provisions gave him a constitutional right to access the DNA evidence for what is known as short-tandem-repeat (STR) testing (at his own expense). The District Court dismissed the claim. The Ninth Circuit reversed, concluding that § 1983 was the proper vehicle for D's claims. The Court of Appeals affirmed, relying on the prosecutorial duty to disclose exculpatory evidence. The Supreme Court granted certiorari to decide whether D's claims could be pursued using § 1983 and whether he has a right under the Due Process Clause to obtain postconviction access to the State's evidence for DNA testing.