KUSHCHEVSKAYA, Russia  The flowers outside the Ametov family’s house in this small farm town have wilted, but two jumpy police officers standing sentry by the wrought-iron gate offer fresh testimony to the horror of what occurred inside.

Twelve people, including four children, were killed at a holiday gathering here last month. Almost all of them were stabbed or strangled and then set on fire. The community’s distress at the brutality was compounded when investigators said that the suspects in the killings were members of a local gang that had sown terror here, unchecked, for years and, worse, had forged close relationships with the local government. Some of the suspects were even current or former elected officials.

As a result of the killings, Kushchevskaya has become a symbol of the epidemic of lawlessness in provincial Russia, a problem rooted in the collusion of bandits and corrupt bureaucrats.

“With every passing day it becomes more and more clear that the fusion of government and criminals, what is now called the Kushchevskaya model, is not unique,” Valery D. Zorkin, the chairman of Russia’s Constitutional Court, wrote in an opinion article on Friday in the government newspaper Rossiiskaya Gazeta. Should the situation continue, he said, “our citizens will become divided between predators, free in the criminal jungle, and subhumans, conscious that they are only prey.”