A new report by Harvard Law School’s Fair Punishment Project has found that a small number of overzealous prosecutors with high rates of misconduct have a hugely disproportionate impact on the death penalty in the United States. The report, America’s Top Five Deadliest Prosecutors: How Overzealous Personalities Drive the Death Penalty, shows that, by themselves, these prosecutors are responsible for more than 440 death sentences, the equivalent of 15% of the entire U.S. death row population today.

Exploring what it calls “the problem of personality-driven capital sentencing,” the report details the effects of Joe Freeman Britt of Robeson County, North Carolina; Robert Macy of Oklahoma County, Oklahoma; Donald Myers of the 11th Judicial District of South Carolina; Lynne Abraham of Philadelphia, Pennsylvania; and Johnny Holmes of Harris County, Texas. Britt, Macy, and Myers personally prosecuted a combined 131 cases that resulted in death sentences, while Abraham and Holmes oversaw offices that the report says imposed 108 and 201 death sentences, respectively. They also disproportionately sent innocent people to death row, prosecuting 1 out of 20 of the nation’s death-row exonerees.

The report found similar patterns involving these prosecutors, including high rates of prosecutorial misconduct, statements and actions that revealed a win-at-all-costs mentality, and a sharp decrease in death sentences once they and their proteges left office. Britt, Macy, and Myers were found to have committed misconduct in one-third to 46% of the death penalty cases they prosecuted. Prosecutors in Abraham’s and Holmes’ offices were found to have engaged in misconduct, including racially-biased jury selection and failures to disclose favorable evidence.

Of the five prosecutors profiled in the report, only Myers—who is not seeking re-election—is still in office. After the other four prosecutors left office, the number of death sentences has declined significantly. Robeson County has imposed two death sentences in the last 10 years, Oklahoma County and Philadelphia County have each imposed three in six years, and Harris County dropped from an average of 12 death sentences a year during Holmes’ last decade as prosecutor to one a year since 2008.

The report also highlights eight other prosecutors who have collectively obtained more than 100 death sentences. The report says that the “over-aggressive and reckless” fervor with which the featured prosecutors pursue death sentences is “evidence that the application of the death penalty is—and always has been—less about the circumstances of the the offense or the characteristics of the person who committed the crime, and more a function of the personality and predilections of the local prosecutors entrusted with the power to seek the ultimate punishment.” It concludes, “[t]his overzealous, personality-driven, win-at-all-costs pursuit of capital punishment seriously undermines the legitimacy of the death penalty today.”