HARRISBURG — Top Senate Democrats were notified about a sexual assault allegation against Sen. Daylin Leach nearly a year ago but launched a formal investigation only after the woman contacted nearly every senator earlier this month, according to emails obtained by the Inquirer and Daily News and the Pittsburgh Post-Gazette.

Cara Taylor, who lives in the Allentown area, wrote in a February 2018 email to Senate Minority Leader Jay Costa (D., Allegheny) that Leach “sexually violated” her nearly 30 years ago, when she was a teenager and Leach was representing her mother in a criminal case. Costa forwarded the information to the chief legal counsel for Senate Democrats, who responded to Taylor that “neither Sen. Costa nor the Senate of Pennsylvania have the authority to review your claims under the Senate’s Workplace Harassment Policy,” according to a copy of the email exchange.

The chief counsel, C.J. Hafner II, noted that the accusations “predate Sen. Leach’s legislative service” and told her she could contact several organizations that offer counseling and referral services.

“I believe they have the experience and resources to assist you,” Hafner wrote.

Earlier this month, Taylor traveled to the Capitol and delivered to nearly every state senator copies of her private criminal complaint against Leach. That is when Senate Democrats decided to hire an outside legal firm to investigate the allegations, which Leach, a Montgomery County Democrat, vigorously denies.

On Thursday night, Costa said he was only “vaguely aware” of the allegations last year. Now that Taylor has submitted a complaint to him and other senators, “members are looking into it and asking questions,” Costa said.

“It’s contrary to where we were before,” he said. “It was not elevated to the point where the alleged victim here was filing a private complaint.”

In her complaint, which has not been formally filed in the court system, Taylor alleges that in 1991, when Leach was a lawyer defending her mother in an attempted homicide case, he lured her into oral sex. At the time, she was 17 and trying to help her mother, she wrote. Taylor falsely took the blame for the attempted homicide — a decision that led to a perjury conviction.

The Inquirer and Daily News and the Post-Gazette typically do not name victims of alleged sexual assault unless they agree to be identified, which Taylor has done.

In an interview Friday, Lehigh County District Attorney Jim Martin said Taylor spoke about the matter with an attorney and an investigator with his office late last year. He said Taylor was told that the allegations fell outside the statute of limitations.

Although his office has not received a formally filed copy of Taylor’s criminal complaint, he said it would have to reject it because the alleged events are too old to prosecute, which would preclude his office from even opening an investigation.

“There would be no purpose in going further,” Martin said.

Senate Democrats this week said they had asked the law firm of Eckert Seamans to conduct a separate investigation on their behalf. It is unclear whether the firm has a timetable for completing its work, the results of which Senate Democrats have promised to share publicly.

Lawyers for the firm did not return requests for comment Friday, and Senate officials did not respond to requests for documents describing the scope of the firm’s work and its cost to taxpayers.

Leach has not responded to requests for comment about the Senate’s inquiry. A statement posted to his Twitter account Thursday night indicated that he intends to file a defamation lawsuit. A spokesperson for Leach did not provide further details, saying that the legal documents were still being finalized.

Asked about the Senate’s investigation, Leach spokesperson Frank Keel said, “Sen. Leach is grateful for any opportunity for due process, as long as it is a fair proceeding.”

The allegations by Taylor have a lengthy history. Her mother, Kathleen Speth, after being convicted of attempted homicide, raised the assault claim in a 1993 complaint filed with the state disciplinary board for attorneys. The board wrote in a letter that there was not enough independent evidence to proceed.

Speth raised it again in an appeal of her conviction. In a hearing, Leach took the stand and denied an inappropriate relationship with Taylor.