In security and compliance, it is often necessary to ensure that agents and systems comply to complex policies. An example from financial reporting is the requirement that every transaction of a customer, who has within the last 30 days been involved in a suspicious transaction, must be reported as suspicious within 2 days.  We present an approach to monitoring such policies formulated in an expressive fragment of metric first-order temporal logic. We also report on case studies in security and compliance monitoring and use these to evaluate both the suitability of this fragment for expressing complex, realistic policies and the efficiency of our monitoring algorithm.