Chandler police documents obtained by The Arizona Republic through a public-records request show repeated incidents of police failing to collect evidence, interview witnesses and document cases.

Chandler Police Chief Sherry Kiyler said it is unusual to have four people aggressively reprimanded for not following leads and investigating cases in one year.

She said the problem is limited to those individuals and does not represent a widespread problem in the department.

In the past three years, the department found at least 44 cases that were mishandled to the point that officers were reprimanded.