RALEIGH — A new report shows that UNC researcher Dr. Eric Miller first was poisoned months before he died. The report is based on tests from Miller's hair collected after he died on December 2.

With the hair sample it is not possible to say precisely when Miller was poisoned, but investigators say it is possible to to get an approximate date.

It could be the key piece of evidence for Raleigh police, but it could also complicate matters for them.

Raleigh police admit they did not expect to have the report of Miller's hair so soon, even though they are in the sixth month of their investigation into the death of the UNC researcher.

"It's a complicated case where we were waiting for a lot of very sensitive medical information come back," says Capt. D.S. Overman. "We have that now and we will continue."

Assistant Chief Medical Examiner Thomas Clark explains that these latest results reveal that Miller was poisoned as far back as last July. The prevailing theory up until this point was that he was first poisoned in November, at a Raleigh bowling alley, after having a beer given to him by his wife's friend and co-worker Derril Willard.

Willard and Miller's wife, Ann Miller, have been closely examined for their possible roles, but the fact that Miller was poisoned as far back as last summer could make it harder to prove who killed him.

Former State Medical Examiner Arthur Davis says that the hair results show Miller was poisoned over a longer period than originally thought, and that more people could have committed the crime. Police admit that this means they will have to question some people again and that they will have to go over evidence again with a fine tooth comb.

"The investigation has a new phase to go into now and it will take longer to conduct it," Overman says.