MEMPHIS — The fatal shooting Wednesday evening of a 20-year-old black man named Brandon Webber, whom the authorities had planned to arrest on outstanding felony warrants, took place on a suburban-style block in front of a brick ranch house with a wide lawn. Then came a violent protest and clash, which left at least 36 law enforcement officers injured.

On Thursday afternoon, scores of African-American residents were crowded on the lawn and in the driveway of the house where Mr. Webber had lived. The air was thick with anger. They shouted about their mistreatment at the hands of the police.

The violent clash between protesters and the police was an explosion of tensions in a city long troubled by poverty, crime and racism. It also unfolded at a moment when the city’s leaders have been trying to build momentum for Memphis by reviving its economy and investing in downtown.

The last week alone has shown how often Memphis, where about one-quarter of the roughly 650,000 residents live in poverty, can veer from hope to despair. Last Thursday, a developer detailed his plans for a project worth at least $190 million. The next night, a business executive was killed after he left a fund-raiser for St. Jude Children’s Research Hospital, one of the city’s pre-eminent institutions.