Illinois law enforcement agencies can refuse to open missing persons investigations on all of the following except:

Illinois law enforcement agencies are required to take specific actions when it comes to missing persons investigations. One significant aspect to understand is that they must prioritize individuals who may be vulnerable or at risk, which includes those with mental health issues or those who may require medication.

Therefore, a person with a mental illness or who is on medication is considered at a higher risk for potential harm or danger when missing, thus requiring law enforcement agencies to open an investigation. This is aligned with the need to ensure the safety and well-being of individuals who may be unable to take care of themselves or who may find themselves in situations where they are at risk due to their condition.

On the other hand, individuals over the age of 21 and those for whom we suspect no foul play may be treated differently under the law. Law enforcement may have more discretion to not open an investigation in those cases, as the perceived risk may be lower. This highlights the importance of focusing on those who may be at greater risk, such as individuals with mental health issues, thereby making the choice about missing persons investigations not just a matter of common procedure, but a reflection of priorities related to public safety and welfare.