DENVER (CBS4) – After a successful career, one explosive detection dog is ready for more naps and rest time.

Rex has been with the Denver Sheriff Department for six years. The City of Denver honored Rex’s career with a retirement ceremony on Wednesday.

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(credit: CBS)

(credit: CBS)

(credit: CBS)

“I do by officially proclaim March 14 … to be K9 Rex Day in Denver, Colorado,” Mayor Michael Hancock said at the ceremony.

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Rex has had a very active career, including assignments dealing with the Aurora theater shootings, visits from presidential candidates, and the Broncos Super Bowl parade last year.

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“Last week, Rex’s handler, Deputy William Swan, took possession of a new 9-month old Malinois, who will eventually take over from but not replace Rex. Rex can never be replaced,” Simon Crittle with the Denver Sheriff Department said in a statement.