BALTIMORE — The Rev. Donte L. Hickman Sr. heard about the trouble brewing on this city’s west side on Monday afternoon and instantly took to Twitter to rally his East Baltimore troops.

“I need all my men to meet me at New Shiloh Baptist Church now,” he wrote, referring to the community hub that had hosted the funeral for Freddie Gray. Days of demonstrations over Mr. Gray’s death after he sustained a severe spinal cord injury in police custody were giving way to violence and looting.

“We have to get these streets under control,” he said in the post, referring to riots in West Baltimore.

About 8:30 p.m., after an emotional meeting and march in West Baltimore that included other pastors, gang leaders and local politicians, Dr. Hickman’s cellphone rang. Back across town, next to his own Southern Baptist Church, a $16 million, half-built senior housing project and community center were ablaze. He had worked for years on the project, an extraordinary investment in a neighborhood that has suffered for years from poverty, drugs and neglect.