It is a problem Chicago police have had a significant hand in building. The culture of mistrust between the department and residents has a foundation based on much more than just the current uproar — the fatal shooting of Laquan McDonald by Officer Jason Van Dyke. Since the early 1980s, the department has repeatedly been tarnished by scandals involving detectives and special units assigned to combat gangs, and who instead have been convicted of committing ganglike crimes such as shaking down drug dealers. A veteran gangs detective said some fault for the spiking violence lies with a department on its heels because of the McDonald scandal.