Which of the following is a key responsibility of a detective?

The key responsibility of a detective is investigating crimes and collecting evidence. Detectives are specialized law enforcement officers tasked with solving crimes, which involves thorough investigations of criminal incidents. This responsibility typically includes interviewing witnesses and suspects, collecting forensic evidence, examining crime scenes, and working with other law enforcement personnel to build a case. By focusing on these activities, detectives aim to uncover the truth behind criminal activities and gather the necessary information to prosecute offenders.

The other options, while important aspects of law enforcement, do not fall under a detective's primary duties. Patrolling neighborhoods is generally the responsibility of patrol officers who maintain public safety and respond to incidents. Conducting traffic stops is also primarily the role of patrol officers, who monitor traffic violations and ensure road safety. Providing personal security for officials is typically assigned to specialized units or bodyguards, who focus on the safety of individuals, including public figures and officials, rather than criminal investigation.