A new study examining the death penalty in North Carolina over a 28-year period makes the same point other studies have made over the years: The race of the victim is a factor in who gets the death penalty.

According to the study, the odds of a death sentence for those suspected of killing whites are three times higher than for those suspected of killing blacks.

And that racial disparity remained, the study found, even taking into consideration whether the person is charged with killing multiple people or with killing someone while committing another felony, such as rape or robbery.

The study was done by Michael Radelet, a professor of sociology at the University of Colorado at Boulder, and Glenn Pierce, a research scientist in the School of Criminology and Criminal Justice at Northeastern University in Boston. The study will be published next year in the N.C. Law Review.

The findings come on the heels of the passage last year of the Racial Justice Act, which allows defendants to use statistics and other evidence to prove racial bias in the application of the death penalty.

People already on death row have until next month to file appeals based on the law. This study as well as another study being done by two Michigan State University professors will provide data that defendants will likely use in their claims.

Other studies over the years have pointed to a clear link between race and the application of the death penalty. A major 2001 study by two UNC professors showed that people convicted of murdering white victims are 3.5 times more likely to be given the death sentence than those convicted of murdering black victims.

But Radelet said this study is the most comprehensive one done on the death penalty and race because it covers a 28-year period between 1980 and 2007. Radelet and Pierce examined 15,281 homicide cases. Out of those, they examined 352 cases in which someone was sentenced to death.

What the study can't explain is why the racial disparity exists, Radelet said.

"We have no evidence that the prosecution is a bunch of bigots," he said. "We're not saying there is overt racism by people who make the decisions. It could be unintentional racial bias."

But the study, Radelet said, makes a clear case that the race of the victim, for whatever reason, is a significant factor in determining who is sentenced to death.

District Attorney Jim O'Neill said he hasn't had a chance to look at the study.

"I hope that the integrity of the study will not be compromised in light of the fact that Professor Radelet has written extensively and spoken out against the death penalty for a number of years," he said.

O'Neill said he also was concerned that the study didn't take into account a number of factors that prosecutors have to consider in pursuing the death penalty, such as the criminal history of the defendant or whether a victim was vulnerable or suffered in the killing.

Radelet said that his opposition to the death penalty has come out of his research.

"You can't come up with results like this and say it's OK," he said.

He said his own feelings don't invalidate the results of his research. Nor should it indicate that supporters of the death penalty can't also do objective research on the issue. He also said that other factors such as how heinous a homicide is are open to interpretation. He said he wanted to limit the factors to things that can easily be analyzed, such as whether there are multiple victims.

Prosecutors across the state have largely opposed the Racial Justice Act. They have argued that the law falsely implies that prosecutors are racists, and that the law is a way to end the death penalty in North Carolina.

"It reduces the decision about the death penalty to statistics," said Peg Dorer, the director of the N.C. Conference of District Attorneys. "What the death penalty is supposed to be about is the assessment of a crime where someone has been murdered and the facts surrounding the crime."

Mark Rabil, an assistant capital defender, said the study confirms what other studies about the death penalty have said.

"The study is consistent with what we've been seeing, that the race of the victim in capital cases is the most significant factor in looking at whether someone gets the death penalty," he said. "It shows that predominantly white juries and prosecutors have been more protective of white life than of minority victims."

mhewlett@wsjournal.com