This study examined how police officers assess for mental illnesses and how those assessments vary by location. Researchers conducted semi-structured interviews with 15 officers working in two police districts in one city. Findings from the study indicate that officers make assessments based on information from dispatch, collateral contacts and behavioral observations on the scene. The study also found that neighborhood context shaped the assessment process due to variations in types of information that were available to officers in different locations. The findings indicate that there is a need to improve the quality of all three sources of information.