Eighteen individuals, including three New York City Housing Authority employees, were arrested after an investigation centered around the Sheepshead and Nostrand houses.

According to investigators, NYCHA continually failed to effectively enforce its "permanent exclusion" policy for dangerous criminal offenders.

The 16-month criminal investigation also uncovered that NYCHA employees were allegedly purchasing drugs from some of the suspects, investigators say.

Two of the defendants were living at NYCHA complexes despite previously being busted for selling crack-cocaine. Eight additional defendants were living in public housing without legal authorization.