NEW HAVEN, Conn. (AP) – Federal authorities vowed Wednesday to vigorously investigate a rash of noose incidents in the state and prosecute those responsible as civil rights leaders decried a lack of arrests in the cases.

The nooses came in the wake of the “Jena Six” case in Louisiana in which white students hung nooses from a tree and black students were charged with beating a white.

“It’s shocking, it’s troubling to learn that Connecticut has probably had more of these incidents since the unfortunate incident in Louisiana than just about any other state in the country,” said U.S. Attorney Kevin O’Connor after meeting with NAACP leaders. “This type of conduct is not going to be tolerated.”

O’Connor, who called the incidents hate crimes, added: “We’re going to start tacking some hides to a shed here if we can.”

A hangman’s noose was found last month in Bridgeport under a black police officer’s patrol car. Other nooses were reported in Stamford and West Hartford.

NAACP leaders welcomed the meeting with O’Connor, but said they were frustrated that no arrests had been made yet.

The U.S. Coast Guard has been investigating cases last summer in which nooses were left in a black cadet’s bag and in the office of a white officer who conducted race relations training after the first incident.

“We will not tolerate this type of behavior,” said Scot Esdaile, president of the Connecticut branch of the National Association for the Advancement of Colored People. “We will not go backwards. It’s very, very embarrassing for the state of Connecticut to be the worst state in the nation right now in reference to this noose situation.”

Esdaile said the incidents are not pranks.

“Eventually what will happen is you’ll start seeing people’s heads in nooses,” he warned.

Michael Jefferson, chairman of the African American Affairs Commission, recalled an incident in Georgia in 1919 in which a pregnant woman was doused in gas and hung after trying to rescue her husband, who was also hung by whites.

“It’s a horrible horrible legacy,” Jefferson said. “I don’t know if the dominant culture can fully appreciate what this means to our community. It’s America’s ancient sin. We refuse to go back to that dark past.”

Federal authorities said they are investigating the cases with state and local authorities and warned those responsible would face prosecution. Authorities cited laws against intimidation that could lead to punishment of up to 10 years in prison, or longer if the crime involves other offenses.

“We do take these cases seriously,” said FBI Special Agent in Charge Kimberly K. Mertz. “I will do everything within my power to solve these cases.”

Mertz and O’Connor urged any one with information on the incidents to come forward. They also said noose incidents should be treated as a crime and reported to authorities.

Gov. M. Jodi Rell has condemned the incidents and pledged her assistance to investigate them.