Baku, October 6 (AZERTAC). In the biggest crackdown on police corruption in the FBI`s 102-year history, authorities charged a total of 133 individuals in Puerto Rico Wednesday as the result of a probe into whether police provided protection for drug dealers.

All but four people, who were still being sought, were arrested Wednesday, authorities said. In all, 89 law enforcement officers and 44 other people were indicted as part of a two-year undercover investigation into 125 drug transactions.

The scope of Operation Guard Shack was also described as unprecedented because 750 FBI personnel were flown to the island to carry out the raids and make arrests, Attorney General Eric Holder said. In total, he said, more than 1,000 FBI personnel participated.

The investigation began when an undercover FBI agent posed as a dealer selling multiple kilograms of cocaine and "put the word out that he needed security during drug deals," the FBI said on its website.

"Many of those who responded were cops. They actively took part in the transactions by carrying weapons and patting down the drug buyers -- who were actually FBI informants."

The cops were paid between $500 and $4,500 for their efforts, the FBI said. "In all, more than $500,000 was paid in protection money."

Puerto Rico is a major shipping point for drugs between the East Coast and such South American countries as Colombia and Peru, said Rosa Emilia Rodriguez-Velez, the U.S. attorney for Puerto Rico.

She described the corruption as limited to a relatively small number of officers "who wanted to make a fast buck ... and needed the money."

"The people of Puerto Rico deserve better," Holder said. He told Puerto Ricans that "as you continue your fight against drug trafficking, violent crime and corruption, we will continue to stand with you."

The 133 defendants have been charged in 26 indictments with charges that include conspiracy to possess with intent to distribute more than 5 kilograms of cocaine, attempt to possess with intent to distribute more than 5 kilograms of cocaine, and use of a firearm during the commission of a drug trafficking offense.

A grand jury in Puerto Rico returned the indictments last month, and they were unsealed Wednesday, officials said.

Arrested were 60 members of the Puerto Rico Police Department, 16 members of various local police departments, 12 correctional officers, eight former law officers, three National Guard soldiers, two U.S. Army officers, one administrative examiner in child support matters, one Social Security Administration employee and 30 other civilians.

The operations began at 3 a.m. ET Wednesday, the FBI said, when 65 tactical teams fanned out across the island, the FBI said. FBI personnel on hand included crisis negotiators, evidence response team members, police dogs and their handlers and 80 medical personnel, including a trauma surgeon and a veterinarian. They traveled in armored Humvees, helicopters and some 250 rental cars, the FBI said.

Some Puerto Rican police officers assisted in the investigation into alleged law enforcement corruption, said Rodriguez-Velez.