Detroit Fire & Policemens Retirement System hired Steward Capital and Fisher Capital to replace INVESCO, which ran a $110 million core equity portfolio, said Walter Stampor, assistant administrative supervisor for the $4 billion pension fund. Steward will receive $40 million and Fisher, $70 million. Columbia Partners will replace Paradigm as a domestic midcap value equity manager. Mr. Stampor expects Columbia will receive $40 million. Both INVESCO and Paradigm were replaced for performance-related reasons, he said. Representatives from INVESCO and Paradigm did not return calls for comment by press time. Gray and Co. assisted.