In a trial lasting just two weeks, prosecutors successfully argued that McQuade was responsible for killing Connolly who was last seen in the early hours of January 7, 1978.
After being spotted at a local bar and then a restaurant in Anchorage, her body was discovered at the bottom of an embankment on the nearby Seward Highway.
A pathologist ruled that she had been raped and murdered, but it was not until advances in technology that authorities were able to piece together her final moments.
Prosecutor Erin McCarthy said investigators at the time had a good idea of what had happened to Connolly, “but at the time they could not get to who”.
“Investigators could not have known over the course of this 40-year investigation that they had collected all the evidence they needed to find Shelley’s murderer on that first day.”
In 2019, DNA technology matched a sample taken from Connolly’s body to McQuade, who was aged 21 and living in Anchorage at the time.
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But the state argued successfully that McQuade killed Connolly during a sexual assault and then dumped her body.
Assistant public defender Benjamin Dresner remained adamant that his client did not kill Connolly.
“Don McQuade did not murder Shelly Connolly. At best, the state’s evidence shows that these two people might have had sex in the day or two before she died,” he said.
McQuade appeared tired as the jury’s verdict was read out. A delay in the trial caused by the pandemic meant he had spent the past few years on bail, but he was taken away from the courthouse in handcuffs.
McQuade’s lawyers are expected to lodge an appeal. He is due for sentencing on April 26.