U.S. authorities will investigate on Sunday the violence stemming from a white nationalist rally a day earlier that killed one person, injured more than 30, and challenged U.S. President Donald Trump’s leadership.

The unrest in the southern college town presented Trump with a domestic crisis, with many on both left and right criticizing him for waiting too long to address it and then, when he did so, failing to explicitly condemn the white-supremacist marchers who ignited the melee.

“Absolutely we are going to have further demonstrations in Charlottesville, because our constitutional rights are being denied,” said Jason Kessler, identified by civil rights groups as a white nationalist blogger. He did not specify when.

Kessler organized the “Unite the Right” rally in Charlottesville against a plan to remove a statue to Confederate war hero Robert E. Lee from a park, saying in a telephone interview those who came in support will not back down.

Four people were arrested in the violence, including James Fields, a 20-year-old white man from Ohio being held in jail on suspicion of plowing a car into a crowd of counter-protesters on Saturday, killing a 32 year-old woman and injuring 19, five of them critically.

Police have not yet provided a motive for the incident but U.S. attorneys and the Federal Bureau of Investigation have opened a civil rights investigation into the crash, an FBI field office said.

Federal authorities were also looking into a helicopter crash on Saturday that killed two Virginia state policemen aiding efforts to quell the clashes.

Virginia Governor Terry McAuliffe, a Democrat, declared an emergency and halted the white nationalist rally planned for Saturday but that did not stop the violence.

About 15 people were injured after rival groups fought pitched battles using fists, rocks and pepper spray.

“Please go home and never come back,” was McAuliffe’s message for the white supremacists, delivered at a news conference.

READ MORE: http://www.reuters.com/article/us-virginia-protests-idUSKCN1AT09B

SOURCE: REUTERS