Police are investigating the shooting death of a protester in Portland; Matt Finn reports.

Acting Homeland Security Secretary Chad Wolf has sent a letter to Portland Mayor Ted Wheeler, urging the Democrat to request federal assistance for his city after months of riots.

“I urge you to prioritize public safety and to request federal assistance to restore law and order in Portland,” Wolf wrote in the letter dated Aug. 31. “We are standing by to support Portland. At the same time, President Trump has made it abundantly clear that there will come a point when state and local officials fail to protect its citizens from violence, the federal government will have no choice but to protect our American citizens.”

Portland has seen over three months of nightly violent protests, including three recent killings, as pro-Trump groups and left-leaning protesters have fought in the streets.