Dog the Bounty Hunter is fuming after his Colorado store was burglarized ... but making matters worse was items belonging to his late wife, Beth Chapman, were also stolen.

Law enforcement sources tell TMZ ... the incident went down Thursday night in Edgewater, CO. We're told the store's front door was shattered. Some of the jacked items include a bunch of "Dog" merchandise but, most importantly, Beth's personal bounty hunting gear.

Dog was told about the incident early Friday morning and took to Twitter to blast the suspects, whom -- as you'd imagine -- he fully intends to track down.

The incident comes just weeks after Dog held a touching memorial service for Beth in Colorado. Family, friends and loved ones gathered to say goodbye for the last time.

As we reported ... Beth died last month in a Honolulu hospital, days after being placed in a medically-induced coma.