Mr. Birkner, MA, MBA, CIH, CSP, was vice president and technical director of McIntyre Birkner and Associates. Mr. Birkner had served in numerous leadership positions in industrial hygiene associations and had managed corporate safety and industrial hygiene programs prior to becoming an expert witness specialist, trainer and consultant. Ms. McIntyre-Birkner was president of McIntyre Birkner and Associates, a consulting and training firm.

Both maintained high profiles and a wide circle of friends and associates within the environmental health and safety field, as organizers and speakers at conferences, authors of magazine articles and books, and volunteers in many projects. Mr. Birkner was an early proponent of industrial hygienists broadening their skills into other areas of the EHS field, making a business case for EHS, and understanding the impact of organizational culture and management systems.

Their loss is felt by Industrial Safety & Hygiene News, as well. Mr. Birkner was a member of ISHN's editorial advisory board in the late 1980s and early 1990s, and gave countless interviews to the magazine over the years.

Police investigators believe the pair were killed on the evening of Monday, February 16, according to an article in the Arizona Republic. The Birkners' house had been ransacked and the couple's two cars were missing when their bodies were discovered Wednesday.

On Thursday, police arrested Timothy Lee Alcorn, 28; his brother Robert Dale Alcorn, 30; and Timothy Robinson, 21, on charges of possessing stolen property, according to the Arizona Republic. Each of the men was considered an investigative lead in the case. According to police, one of the men knew the Birkners and had done work at their home.