While expert evidence about bitemarks is widely discredited as unreliable, it has played an unfortunate role in assuring the wrongful convictions of innocent defendants. A defendant in Pennsylvania whose conviction was overturned because (among other reasons) it was based on bitemark evidence sued the police and prosecutors for building a case against her that they knew to be baseless. The Court of Appeals for the Third Circuit was recently asked whether the prosecutor was immune from liability for the role he played in directing the bitemark evidence investigation.

Facts of the Case

In 2001, police officers in Connellsville, Pennsylvania found the body of Curtis Haith on a sidewalk. Haith had been beaten and shot. The police asked Nancy Vernon, the District Attorney for Fayette County, to come to the scene and direct the investigation.

Police investigators learned that Haith had hosted a party and attended other parties the night before his body was discovered. They found evidence of drug use in Haith’s apartment.

Interviews with people who attended Haith’s party prompted the investigators to contact Crystal Dawn Weimer. She appeared to have minor injuries. The investigators noticed mud and blood on her clothing.

Weimer told the police that she had given Haith a ride from one party to another. She then spent the rest of the night with her mother and sisters. They confirmed spending the night with Weimer, as did her boyfriend, Michael Gibson.

Weimer explained that the blood on her clothing came from a fight with Gibson. A DNA test confirmed that the blood came from Gibson. None of Weimer’s blood was found at the crime scene, although blood was discovered that came from an unidentified male.

Nearly two years later, a man Weimer had dated before Gibson, Thomas Beal, told the police that Gibson and Weimer killed Haith. Beal claimed that Weimer admitted that the blood on her clothing came from Haith. Since DNA testing had confirmed that the blood was not Haith’s, the police should have known that Beal was lying to them.

Bitemark Evidence

The state police then joined the investigation. They saw what they believed to be a bitemark on a photograph of Haith’s hand. A local dentist compared the photograph to the teeth of Gibson and Weimer and said she could not tell which of them bit Haith.

A bitemark “expert” then compared the photograph to dental impressions from Gibson and Weimer. The “expert” opined that Weimer caused the bitemark. When a question later arose about the timing of the bitemark, the “expert” proclaimed that the bite occurred seven to ten minutes before Haith’s death. He offered that opinion without conducting any additional research.

Beal later changed his story, implicating a man who was in prison at the time of the murder. The District Attorney nevertheless decided to pursue a murder charge against Weimer based on Beal’s first story and the opinions offered by the bitemark analyst.

A prison witness surfaced who claimed that the murder was committed by Weimer, Gibson, and Beal. That witness implicated another prisoner, Joseph Stenger, who supposedly wrote a statement confessing his participation in the crime. Stenger denied writing the statement.

Weimer’s Trial

The evidence against Weimer was obviously so inconsistent that no conscientious prosecutor would have believed that it proved guilt beyond a reasonable doubt. Three years after Haith’s death, police officers nevertheless prepared a criminal complaint charging Weimer with his murder. Vernon approved the complaint, leading to Weimer’s arrest.

According to the appellate court, “the case against Weimer fell apart almost immediately.” At a preliminary examination, Beal admitted that the police had coached him to give testimony implicating Weimer. A judge dismissed the charges because of that recantation.

Undeterred, the police again approached Stenger, hoping to obtain new evidence against Weimer. Stenger agreed to testify against Weimer in exchange for a reduced sentence. A jailhouse snitch who testifies in exchange for a reward should never be viewed as a credible witness, but Weimer was recharged on the strength of that dubious evidence.

Stenger and the state’s bitemark expert provided the only significant evidence against Weimer at her trial. A jury found her guilty in 2006.

Weimer’s Exoneration

In 2015, a judge determined that police and prosecutors acted improperly to obtain Weimer’s conviction. By that time, having obtained the benefit of his lie, Stenger was willing to admit that he knew nothing about Haith’s murder and that his testimony was prepared by the police.

Other jailhouse informants testified that they never asked for or received deals in exchange for their testimony. Weimer’s new lawyers discovered letters in the prosecutor’s file proving that the informants had, in fact, offered to trade favorable testimony for favors.

Critically, the bitemark expert also disavowed his trial testimony. The expert admitted that bitemark identification is junk science.

A defense expert reviewed Haith’s autopsy and photographs of Weimer’s injuries. The expert concluded that Weimer’s injuries were consistent with her statement that they occurred a few days before Haith’s death.

Based on the new evidence, a judge granted Weimer a new trial. Having no remaining evidence other than statements by obvious liars, the prosecution then dropped the charges.

Weimer’s Civil Rights Lawsuits

Weimer sued the county and city, several police officers, and Vernon for violating her civil rights. The legal theories she asserted against Vernon included malicious prosecution and the failure to intervene to prevent the police from violating her civil rights.

Vernon moved to dismiss the complaint on the ground that prosecutors are absolutely immune from liability for their official conduct in prosecuting a case. The trial judge agreed that Vernon could not be sued for actions taken in the prosecution phase of the case, but concluded that Vernon was not absolutely immune for actions she took when she directed the police in their investigation of Weimer.

The judge dismissed the malicious prosecution claim except to the extent that it was premised on the bitemark investigation. The judge allowed Weimer to amend her complaint to allege more specific facts about the role Vernon played in directing the investigation of the bitemark.

After Weimer amended her complaint, Vernon renewed his motion to dismiss. The trial judge denied the motion. The judge ruled that Weimer alleged sufficient facts that, if proved, would demonstrate that Vernon allowed the police to build a case that Vernon knew was meritless. Vernon appealed, contending that he was entitled to absolute or qualified immunity from liability.

Appellate Opinion

The Court of Appeals for the Third Circuit agreed that a prosecutor’s absolute immunity only extends to actions that are closely associated with the judicial phases of a prosecution, such as presenting evidence in court. Administrative or investigative actions do not entitle a prosecutor to absolute immunity.

The court agreed that Vernon’s conduct at the crime scene was investigative in nature. Vernon was also engaged in investigative duties while overseeing a police investigation that produced and relied upon conflicting statements. Vernon was not entitled to absolute immunity for those actions. She was, however, immune from liability for her decision to prosecute Weimer based on such shaky evidence.

The court nevertheless found that Vernon had qualified immunity from liability based on the claim that she failed to intervene in the police investigation. Qualified immunity is a controversial doctrine that shields government employees from liability for constitutional violations when the specific conduct for which they are sued has not been clearly established as the violation of a constitutional right. The court concluded that the right to have a prosecutor intervene to protect a defendant from a meritless prosecution had not been clearly established.

The appellate court also disagreed with the trial judge that Vernon had a clearly established duty not to tell the police to rely on the junk science of bitemark identification. Vernon realized that the mark on Haith’s hand might not have occurred on the day of his murder, so she asked the police to obtain expert evidence about the timing of the bitemark. The police returned to the expert who, without reviewing any new evidence, claimed to know that that the bitemark was caused shortly before his death. The prosecutor’s bad faith in relying on such doubtful evidence seems apparent.

The appellate court nevertheless decided that defendants have no clearly established constitutional right not to have prosecutors direct an investigation based on junk science. The court noted that during the 2002 to 2006 time frame, prosecutors often presented bitemark evidence in support of prosecutions. According to the court of appeals, the unreliability of bitemark evidence was not widely accepted until a few years later.

Prosecutors fought (and continue to fight) vigorously against the recognition that bitemark evidence is junk science. Their resistance to science that gets in the way of convictions explains why it took courts so long to agree that bitemark evidence is useless. Their success in convincing courts and juries to accept unreliable science shielded Vernon from liability for telling the police to obtain bitemark evidence from an expert who now concedes that his opinion was groundless.

Fortunately, Weimer will be able to continue her case against the police officers who allegedly coerced witnesses to change their stories and hid exculpatory evidence from the defense. When and if the case will settle or go to trial is yet unknown.