The Hebrew Immigrant Aid Society, or HIAS, known for its resettlement work in the United States and internationally, is one of the oldest refugee protection agencies in the country. The organization became part of the national conversation Saturday after the man accused of shooting and killing 11 at a synagogue in Pittsburgh appeared to have referred to the group online.

In a post on the social network Gab, the accused shooter, Robert Bowers, 46, linked to a directory of synagogues participating in a HIAS event, National Refugee Shabbat, saying he "appreciated" the list. As part of the elaborate anti-Semitic conspiracy theory to which he subscribed — which prosecutors say motivated his crime — Bowers claimed that HIAS was working to bring people to the United States to do violence.

Scott Brady, the U.S. attorney for Pittsburgh, said federal prosecutors were seeking approval from the Justice Department to pursue the death penalty, The Associated Press reported Sunday night.

Founded in 1881 as a storefront on the Lower East Side of Manhattan, the organization began as a mission to help Eastern European Jews who were fleeing anti-Semitism and war.

"We have made a lot of progress in the past two years in getting attention to our work, but yesterday, things took a turn," said Bill Swersey, a spokesman for HIAS.

In 1980, HIAS became an official voluntary agency for the State Department's Office of Refugee Resettlement, joining eight other organizations, which include other religious-based groups like Lutheran Immigration and Refugee Services and the Church World Service.

The U.S. government refers immigration cases to HIAS, which works with 20 sites and affiliates across the country to help resettle refugees. Most of the people working on the ground to deploy resources are associated with Jewish family centers.

Nearly two decades ago, it began to help non-Jewish immigrants from countries like the Republic of Congo, Afghanistan and Syria — mainly resettling migrants from war-torn countries and providing them with housing and financial and job assistance.

"As our president likes to say, 'We used to help refugees because they were Jewish but now we help refugees because we're Jewish,'" Swersey said.

HIAS is also involved in immigration causes around the world through its 10 international offices. The recent issues at the U.S.-Mexico border and a migrant caravan have also become part of their work.

"As far as the migrant caravan goes, we are actively advocating for asylum seekers," Swersey said.

HIAS held its National Refugee Shabbat on Oct. 19 and 20 across the country so congregations could "deepen" their understanding of the refugee crisis. Speakers included Ahed Festuk, a Syrian activist from Aleppo, and Debora Barrios-Vasquez, who recently resettled in the United States after fleeing Guatemala.

"If you look on social media, you will see people who are against our work in accepting immigrants and helping them, but this is the first time we have ever seen it expressed in violence, at least towards us," Swersey said. "People have criticized us before, but no one has ever taken it this far."

He said the humanitarian aid group doesn't believe that Bowers called it out because of its Jewish roots but because it is assisting immigrants in finding refuge in the United States.

"I think what [Bowers] was responding to is the idea of the Jewish community supporting other people coming to live here," Swersey said. "This is an elevation of the issue of anti-immigration, and it's a concern to us and should be a concern to all Americans."