Nearly three hours before a mass shooting turned a south Baltimore neighborhood block party into a scene of terror and bloodshed, the city’s police department received a call about hundreds of partygoers armed with guns and knives — but on-duty officers decided no police services were required. Baltimore’s troubled history with policing was thrust into the national spotlight years ago following the 2015 death of Freddie Gray in police custody. Since then, city leaders have focused on reforming the Baltimore Police Department and repairing public trust, especially within ...