Following a rash of deaths, threats and violent acts, Americans fear the nation may be growing so far apart that danger may become a regular factor in partisan disputes. It has happened before.

Homeland security expert Juliette Kayyem believes the Tree of Life synagogue shooter may have been radicalized through social media.

The National Fire Protection Association has a plan to improve collaboration among first responders at the scene of an active shooter.

"President Trump, you are not welcome in Pittsburgh until you fully denounce white nationalism," an open letter from progressive Jewish leaders read.

For many in Pittsburgh's Jewish community, Tuesday's funerals for Cecil and David Rosenthal start the formal period of mourning for victims — a process carefully guided by Jewish tradition.

President Donald Trump's response to the deadliest incident of antisemitic violence in American history is raising a debate about whether houses of worship should start hiring armed guards for protection.

A spokeswoman dismissed suggestions that Trump's rhetoric has contributed to a hostile climate. She said Trump won't shy away from drawing distinctions with Democrats before the midterm elections.

The police chief of Jeffersontown, Ky., says the attack was racially motivated, and federal prosecutors say they're investigating whether the murders are hate crimes.

Sessions said that Tree of Life Synagogue congregants were “targeted because of their faith and that the Justice Department and FBI intend to do our duty in this matter,” including seeking the death penalty for the accused killer.

The website where the synagogue shooting suspect posted anti-Semitic messages has served as a home for the far-right online in Gab's quest to have few restrictions on speech.