A blast from a “modified, loaded shotgun” injured three Kansas police officers Saturday afternoon as they checked out a vacant home, the AP reports. One of the officers was treated and released from the hospital, per KWCH. The two others remained hospitalized Sunday, according to reports, one with minor injuries and the other in serious but stable condition. Authorities say that a homeowner called police to report damage to a vacant home in Wichita, the Wichita Police Department said in a statement. The officers got the keys from the homeowner, who believed someone might be inside. When they entered through the front door, there was an explosion. “The investigation revealed that no one was inside the home, but someone had left a modified, loaded shotgun in the residence which discharged as the officers made entry,” the department said. A police representative told CNN on Sunday that an investigation is ongoing. (More booby trap stories.)