As Thai authorities investigate Thursday¡¯s ghastly mass killing of 36 people by a former police officer, they are also confronting the role of their own ranks in the country¡¯s distorted gun market and gun culture.

The gunman, Panya Kamrab, 34, used a 9 mm pistol he obtained legally, police said. He also owned a shotgun. And before he was fired from the police force in June on drug possession charges, both would have been easy for him to buy. Thailand¡¯s security forces can purchase as many weapons as they want through the government, and at a steep discount.

Civilians seeking to buy guns, by contrast, face tough laws and high prices ¡ª a disparity that creates perverse incentives and other problems. In some cases, it has led those charged with public safety to sell caches of weapons for profit.