Attorney General Roy Cooper says the state needs tools to investigate former Durham County District Attorney Mike Nifong.

State and local authorities have long relied on help from federal prosecutors, who can convene investigative grand juries and charge people with lying to investigators. Under state law, those grand juries can only investigate drug conspiracy cases.

The feds have helped in the public corruption cases of former House Speaker Jim Black and Agriculture Commissioner Meg Scott Phipps. But the U.S. Department of Justice will not help in the Nifong case.

"We can't expect federal authorities to help us every time we ask," Cooper said. "(But) the refusal of federal authorities to get involved makes it difficult to conduct (an) additional investigation." (AP)