Eight families say a teacher at a Jewish preschool in Washington repeatedly sexually abused their children over the past two years, and they contend the school's leader and a prominent synagogue did nothing about it despite warnings.

Claims of sexual abuse against children ages 2 to 4 are outlined in a civil lawsuit filed late Monday against the Washington Hebrew Congregation, which operates the Edlavitch Tyser Early Childhood Center, and its head of schools, Deborah "DJ" Schneider Jensen.

The suit, filed in the Superior Court for the District of Columbia, alleges the defendants enabled sexual abuse of children by the same man – Jordan Silverman, an assistant teacher who arrived at the preschool in 2016 after a long career as a photographer in Vermont.

Attorneys for the parents and children say the abuse, which spanned from March 2016 to August 2018 on the preschool's campus, included the "most grievous, demeaning and damaging forms of sexual abuse" and was "systemic and regular." The victims were girls and boys, they say.

The lawsuit's 23 plaintiffs – children and their parents – are pursuing several claims of negligence, arguing the school and Jensen are liable for allowing the abuse to persist. They contend that Silverman was "allowed and encouraged" to be alone with the children with no other adult present. They say that violated a Washington "two-deep" policy that requires at least two adults to be present with children at all times at licensed child development centers.

"Essential protection against abuse of this type in a child-caring environment requires visibility and accountability of all adults present at all times," the lawsuit reads. "Defendants provided for neither."

The suit, which lists seven children only as Jane and John Does and keeps the parents anonymous as well, seeks an amount of compensation to be determined by a jury for damages, both monetary and non-monetary.

Silverman, who was not named as a defendant in the lawsuit, has not been charged with any crimes and denies the allegations in the lawsuit. His lawyer, Shawn Sukumar, told CNN that Silverman contends he did nothing inappropriate.

"Mr. Silverman categorically denies engaging in any inappropriate or illegal contact with children at Washington Hebrew Congregation," Sukumar told CNN.

In August, The Washington Post reported that District of Columbia police were investigating allegations of sexual abuse at the Washington Hebrew Congregation preschool.

A statement on behalf of Washington Hebrew Congregation in response to the lawsuit said the synagogue is "carefully reviewing the complaint." The temple's leaders say they reported the sexual abuse allegations in August as soon as they learned of them and have "continually and fully cooperated" with the criminal investigation.

"Child safety has always been our top priority," the statement reads. It rejects allegations that the early childhood center violated the law or state regulations.

"Although there has not been any arrest, these allegations are very troubling; as a faith community, Washington Hebrew has supported and will continue to support its entire community as individuals grapple with how these allegations affect them and their families," the statement says.

Jensen did not respond for a request to comment.

The Washington Hebrew Congregation sent a letter to parents in August that said an employee at its early childhood center was put on administrative leave after allegations that the employee "may have engaged in inappropriate conduct involving one or more children." The school did not disclose the name of the employee at the request of police.

Plaintiffs are represented by the Sexual Abuse, Sex Trafficking and Domestic Violence group of the Washington-based law firm Cohen Milstein Sellers & Toll, which specializes in whistle-blower cases against corporations and antitrust, civil rights and human rights cases.

"Silverman’s alleged behavior is only a part of this story," Steve Toll, managing partner of the law firm, said in a statement. The preschool and Jensen "not only created an environment that enabled this predatory behavior but failed to act on a myriad of indications that something was wrong."

"They must be held accountable so that no child in this program ever suffers again," Toll said.

Jensen, who was hired by Washington Hebrew Congregation to lead the early childhood center in 2014, announced in February plans to leave her position after the end of the academic year. In a letter on her departure, she said it's time to pursue other initiatives in early childhood education, finish writing her second book and focus on training teachers. She did not refer to the sexual abuse investigation.