"It's been 17 years, we're sorry you made a mistake," defense attorney Andrew Lambert said to prosecutors.
The victim's mother, Karen Foster, says Craig had a boyfriend and didn't have time for a secret relationship with Dion.
"There's no way Bonnie would have a relationship with that man," prosecutor Paul Miovas said.
Lambert says his client, Kenneth Dion, was never at the crime scene. The defense's theory is Craig stopped to talk with two men in a yellow or tan Toyota Corolla after arriving at UAA before her morning classes.
Witnesses for the defense are expected to testify they saw Craig get in the car and leave with the unknown men. The men in the Toyota were described as dark-haired, Dion had flaming red hair at the time.
Lambert claims no one can place Dion at McHugh Creek where Craig's body was found.
"There's no proof he was even there," Lambert said.
A hiker in the area, Arndt von Hippel, told police he saw Craig seemingly happy and safe on a trial with four other people. The hiker was able to identify Craig from a line-up and accurately described what she was wearing. In its opening statement Tuesday the prosecution suggested von Hippel mistakenly identified Craig.
The attorneys disagree on certain aspects of the medical examiner’s analysis, including: whether injuries on the victim's hands were defensive wounds, when Dion and Craig had sex, and whether the head lacerations on Craig's body were a result of a beating with a tire iron or caused by jagged rocks along the cliff face she was found under.
Of the 500 pictures taken at the scene, none depict blood or signs of a struggle. The defense says there are no signs of violence at the scene, which suggest to him Craig accidentally fell to her death.
Prosecutors admit the lead investigator at the scene was inexperienced and made mistakes.