Several years ago, on a hot July night, a little girl named Elizabeth Knapp was raped and murdered in Contoocook, N.H.

The mother’s live-in boyfriend, Richard Buchanan, became the prime suspect and was charged with first-degree murder. This quickly became a highly publicized case and the N.H. attorney general was being pressured in the press, and by members of the legislature to upgrade the charge to capital murder and seek the death penalty. As a public defender, I was assigned to represent Mr. Buchanan.

The evidence against Buchanan seemed overwhelming. This little girl was raped and murdered just feet away from her mother’s bedroom. She was sleeping virtually inches away from her sister in a very small cluttered apartment. It seemed impossible that a stranger could have entered the home and not wakened anyone. There were no signs of forced entry. And to make matters worse, after over seven hours of intense police interrogation, Elizabeth’s mother told the police that she witnessed Buchanan rape and strangle Elizabeth.

Even I assumed my client was guilty.

However, Richard Buchanan was innocent. The real person who raped and murdered Elizabeth had not worn a condom, and the true killer’s semen was collected from Elizabeth’s body. DNA tests proved that Buchanan was not the assailant and the charges against him were dropped.

Many people believe that innocent people can’t be wrongfully convicted in New Hampshire. It may happen in other places, but not here. But my personal experience tells me that New Hampshire is not immune to human errors, mistakes and snap judgments and that an innocent person could be convicted and executed here for a crime they did not commit.

Richard Buchanan was eventually freed, but I don’t take much comfort in that. In Buchanan’s case, he was lucky that the real assailant had not used a condom. If he had used a condom, there would have been no DNA evidence to exonerate Mr. Buchanan. The jury would have been rightly outraged by the brutality of this little girl being raped and strangled in her own bed and would have likely sentenced this innocent man to death.

I have been a trial lawyer in N.H. for over 30 years, 14 of which I served as a public defender and prosecutor in the New Hampshire Attorney General’s office. During those years I saw my share of mistakes: Incomplete investigations, false confessions, incorrect eyewitness testimony, lab technicians using outdated equipment, and attorneys who misunderstand or mischaracterize evidence. Any of these can lead to unfair results. Well-meaning, educated people, all wanting to do the right thing – and still mistakes get made.

We don’t use the death penalty often here in New Hampshire, but our system is flawed and as long as the law is on the books there is a real risk that we will execute an innocent person.

Barbara Keshen is a former homicide prosecutor for the New Hampshire Attorney General’s Office and currently serves as Chair of The New Hampshire Coalition to Abolish the Death Penalty (NHCADP). NHCADP has been operating since 1999 and has more than 2500 members. The NHCADP’s leaders include victim families, clergy, law enforcement, corrections officials, former Supreme and Superior Court Justices and former Attorneys General.