For decades, in cities from coast to coast, FBI agents recruited killers and crime bosses as informants and then looked the other way as they continued to commit violent crimes.

When the practice first came to light in Boston - unleashing an ongoing investigation that has already sent one agent to prison for obstruction of justice - FBI officials in Washington portrayed it as an aberration.

But AP interviews with nine former FBI agents - men with a combined 190 years of experience in more than 25 bureau offices from Texas to Chicago and from Los Angeles to Washington - indicate the practice was widespread during their years of service between the late 1950s and the 1990s.

Some of the arguments made by the agents resemble arguments made in defense of torture and other such means:

"You have to weigh the odds of whether killing one or two people is better than killing a whole planeload," said Wesley Swearingen, whose service as an agent from 1959 to 1977 included tours in Los Angeles and Chicago.

Combine an institutional willingness to look the other way with the war on terrorism (and the proposed Patriot Act II), and a dangerous stew could be brewing.