BALTIMORE — The Rev. Donté L. Hickman Sr., pastor of one of this city’s largest African-American churches, wrapped up a fiery, foot-stomping sermon one recent Sunday with a somber request. “Pray for the city and the mayor,” he urged his congregation, reminding them that Mayor Stephanie Rawlings-Blake had decided not to run again.

Instead, the chapel erupted in cheers.

Across the street from the Southern Baptist Church in East Baltimore, which Mr. Hickman has led for 13 years, a $16 million church-sponsored apartment complex and community center — half-built and set ablaze during riots in April — is again rising from the ground, an upbeat sign in a neighborhood of dilapidated and abandoned rowhouses. But Mr. Hickman says it will take more than “brick and mortar” rebuilding for the city to heal.

“Baltimore,” he warned, “is on the brink of a breakthrough — or a breakdown.”

Six months after a 25-year-old black man, Freddie Gray, died after suffering a spinal cord injury in police custody, setting off the worst riots here since the 1968 assassination of the Rev. Dr. Martin Luther King Jr., this waterfront city is fragile and on edge. Baltimore is in search of new leadership and unsure of its future, as it braces for the trials of six police officers implicated in Mr. Gray’s death.

The homicide rate is soaring. Baltimore, with roughly 623,000 people, has had 270 homicides this year, almost as many as in New York, with 281 in a city of about 8.4 million. Nearly 100 people have been murdered in Baltimore in the last three months alone, eight in the last week. Residents, angry and frightened, accuse the police of standing down and ignoring crime.