An estranged couple who had hunted ghosts together on reality TV were found dead Tuesday after a SWAT standoff at a Nevada apartment.

Mark and Debby Constantino specialized in electronic voice phenomena and had appeared on the Travel Channel's Ghost Adventures. Their work also was featured on other shows, as well as at paranormal conferences, and live ghost hunts.

According to KTVN, Debby Constantino's roommate called police in Sparks, Nevada, on Tuesday morning upon finding her missing from their apartment and their other roommate, who has not been identified, dead.

Police were able to track Constantino's cell phone to another apartment, where they found she was being held by her estranged husband, according to KTVN. Mark Constantino fired several shots at police as they approached, the Associated Press reported, but police did not return fire.

He told officers, "Give me 15 minutes to gather my thoughts or I'll kill her," police told the Reno Gazette-Journal.

A standoff ensued for hours before police stormed the door. Inside, they found both Constantinos dead. Mark Constantino was also considered a suspect in the death of the man at his wife's apartment, police said.

According to court records, Debby Constantino had filed for divorce on Sept. 10. She and her husband had also previously applied for restraining orders against each other.