On October 27, 2018, a mass shooting occurred at the Tree of Life – Or L'Simcha Congregation synagogue in the Squirrel Hill neighborhood of Pittsburgh, Pennsylvania. The congregation, along with New Light Congregation and Congregation Dor Hadash, which also worshiped in the building, was attacked during Shabbat morning services. The perpetrator, 46-year-old Robert Gregory Bowers, killed eleven people and wounded six, in the deadliest attack on a local Jewish community in American history. After being shot multiple times by police, Bowers was arrested at the scene. Bowers had earlier posted antisemitic comments against HIAS (formerly, Hebrew Immigrant Aid Society) on the online alt-tech social network Gab. Dor Hadash had participated in HIAS's National Refugee Shabbat the previous week. Referring to Central American migrant caravans and immigrants, Bowers posted a message on Gab in which he wrote that "HIAS likes to bring invaders in that kill our people. I can't sit by and watch my people get slaughtered. Screw your optics, I'm going in." He was charged with 63 federal crimes, some of them capital crimes. Bowers pleaded not guilty. In 2023, he was found guilty on all counts and sentenced to death by lethal injection. The shooting was widely condemned. President Donald Trump's visit to Pittsburgh in the aftermath of the attack was met by protests, with some blaming him for an upsurge in white nationalist violence. In the years following the attack efforts were made to increase security at American synagogues and other Jewish buildings. Millions of dollars were raised for victims and survivors of the attack. There are plans to build a memorial complex at the site of the shooting.