PORTLAND — The hearing on Dennis Dechaine’s bid for a new trial today featured expert witnesses with conflicting views about the likelihood that the DNA evidence at issue was the result of contamination.

Dechaine is serving a life sentence for the 1988 kidnapping and murder of 12-year-old Sarah Cherry of Bowdoin.

A state law allows prisoners to seek new trials based on DNA evidence. Dechaine must convince his original trial judge, Superior Court Justice Carl Bradford, that jurors would not have convicted him had they known about male DNA from Sarah Cherry’s fingernail.

Dechaine’s lawyer says the partial DNA profile from an unknown male may point to an alternative suspect. The state maintains that the DNA is likely a result of contamination.

Two witnesses for the state – Frederick Bieber of Harvard Medical School and Carll Ladd of the Connecticut forensics lab – agreed that the conditions in which Sarah Cherry’s autopsy took place were ripe for contamination.

Previous testimony at the multi-day hearing indicated that autopsy instruments were not sterilized, not necessarily washed and stored in tool drawers lined with towels that would become soiled with blood over time.

But another geneticist, Greg Hampikian, of Boise State University, testified for the defense he did not believe rampant contamination was responsible for the DNA on the nail clipping. If that had been the case, he said, the male DNA also would have been found on the right thumbnail clipping since they were taken at the same time with the same instrument under the same conditions.

No more testimony is scheduled for the hearing this week. The parties may reconvene after the results of additional DNA testing on certain items of evidence become available. That will likely take a couple of months.