It happened around 2:45am on Casa Grande near Merritt Lane.
Houston police said the security guard saw several suspects running from a vacant apartment that caught fire. The guard chased them and was shot in the parking lot.
Emergency crews arrived and transported the man to the hospital, where he died.
"It appears at this time, witnesses did see two to three males leaving the scene," HPD Officer V. McLean said. "We are just trying to develop leads."
This case remains under investigation. Police have not released details on possible suspects.
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