Rape and sexual assault charges against lawyer and former Montgomery County GOP Chairman Robert Kerns were dropped Monday because of a misinterpreted toxicology report.

Montgomery County District Attorney Risa Vetri Ferman said in a statement that her office made the decision to drop all 19 charges against Kerns based on a discovery that a member of the district attorney’s investigative team misinterpreted a piece of evidence in the case.

Ferman said in her statement that because the investigating grand jury in the case made its charging recommendations based upon inaccurate evidence, dropping the charges was the only course of action.

Kerns was accused of drugging and assaulting an employee of his law firm. The charges against him included rape of an unconscious victim, rape of an impaired person, sexual assault, aggravated indecent assault, possession of a controlled substance, possession with the intent to manufacture or deliver and tampering with/fabricating physical evidence, according to the docket.

The misinterpreted evidence in question, Ferman said, was a toxicology report that was thought to have found Zolpidem, also known as Ambien, in Kerns’ accuser’s system.

“At issue is the lab analysis of the report, which appeared to indicate an identifiable value related to the presence of the drug Zolpidem,” Ferman said. “The investigator incorrectly interpreted that value as meaning that the lab discovered trace amounts of the drug in the complainant’s system. In fact, the proper conclusion was that the lab did not find any amount of the drug Zolpidem in the complainant at all.”

Ferman said that the case has been referred to the office of state Attorney General Kathleen Kane to find out if charges can be refiled and to handle any future prosecution in the case.

“I am just greatly relieved that we were able to discover that a terrible mistake had been made, and were able to put an end to this and get Bob his life back,” Kerns’ attorney, Brian McMonagle of McMonagle, Perri, McHugh & Mischak, said.

McMonagle added that he contacted the District Attorney’s Office as soon as the defense’s investigation had uncovered the mistake, and that the district attorney immediately took action to “right in my mind what was a terrible wrong.”

“It is my belief that it was a very unintentional mistake, and I’m just relieved for Bob and his family,” McMonagle said.

The prosecutor in the case, Assistant District Attorney Samantha Louise Root Cauffman, did not return a call seeking comment.

At a Dec. 20 hearing, Kerns’ accuser testified that she felt “groggy” after drinking wine Kerns had offered her in his car, after Kerns had offered her a ride home from a work-related party. The woman said that Kerns raped and sexually abused her in his car and then drove her to her home and assaulted her once more.

Lt. Christopher Kuklentz testified at the hearing that a urinalysis revealed that the woman had traces of Ambien in her system. He also read from an interview transcript in which he questioned Kerns about the alleged incident.

Kuklentz had mentioned that during the interview Kerns was perspiring and had “beads of sweat on his forehead.” Kuklentz also told the court that after the interview, he pressed Kerns to tell him the truth “and asked him what went wrong that night. He said he had to think about it.”

A vacuum swab of the victim’s clothing showed a single “male DNA profile consistent with the defendant’s,” Kuklentz had said.

Kuklentz had said additionally that, “I confronted [Kerns] and asked how he would explain if his DNA was found on [the alleged victim's] undergarments. He said his hands could have slipped under her garments” and made contact with the alleged victim.

McMonagle had asked Kuklentz if the DNA testing done on the alleged victim and her clothing revealed any semen. Kuklentz said the tests did not.

P.J. D’Annunzio can be contacted at 215-557-2315 or Follow him on Twitter @PJDannunzioTLI. •