BY FRANCES ROBLES

Every time law enforcement officers in Puerto Rico closed in on the island's most-wanted fugitive last year, drug trafficker Alex Trujillo skipped out just in time.

He was captured only after the joint federal and local task force hunting him down was cut in half to weed out suspected insider informants, Police Superintendent Pedro Toledo said.

And after investigators at Puerto Rico's Justice Department saw several drug stings flop last fall, prosecutors discovered a department employee who was tipping off drug dealers. Aurea Teresa Cancio Nieves was caught on camera taking $1,500 from an undercover agent, court records show.

As Puerto Rico battles one of the highest crime rates in the United States and burgeoning drug trafficking blamed for about 700 murders a year, authorities are confronting another harsh reality: corruption.

About 100 police officers are currently under investigation, and 75 others have been convicted in federal court in the past five years, law enforcement officials said. The Puerto Rican attorney general's office has 17 open cases against members of the police department.

As a hub for cocaine and heroin arriving from Colombia on the way to mainland U.S. streets, Puerto Rico is so steeped in drug corruption that even a top prosecutor was accused of accepting a Mercedes Benz from a known dealer. The U.S. government estimates that 20 percent of the cocaine from Colombia passes through the Caribbean.

''We have had officers using police cars to escort drug dealers, and we have arrested officers selling weapons to undercover agents,'' Toledo said. ``We have many honest, hard-working officers, but some violate their oath. We have to get rid of them. We are not going to cover up corruption.''

Between 1993 and 2000, the Puerto Rico Police Department expelled 1,000 police officers on a variety of criminal charges, Toledo said. But he stressed that there are about 20,000 officers across the island of 4 million people -- one of the world's highest police-per-capita ratios -- making the corrupt officers a comparatively small minority.

In November, two officers assigned to the Arecibo station on the north coast were sentenced to 65 years in prison for protecting cocaine shipments. Another got 40 years.

`LOST HONOR'

In 2001, 32 officers were arrested in the biggest police corruption case in the island's history, dubbed ''Operation Lost Honor.'' Officers were accused of using their patrol cars to protect cocaine shipments.

In 2004, 16 officers, including two women, were charged with conspiring to sell drugs in ''Operation Dark Justice.'' In yet another police corruption case, ''Blue Shame,'' prosecutors publicly complained that they suspected judges involved in the case were corrupt.

''This is not something new,'' said Luis S. Fraticelli, special agent in charge of the FBI's San Juan office. ``This has has been going on in Puerto Rico as long as I can remember.''

In the 1970s, he said, corruption was so rampant that some officers were charged with murder.

''We have had undercover agents pose as drug traffickers who hire corrupt police officers to protect shipments of 30 kilos,'' Fraticelli said in a recent interview. ``To protect that shipment from point A to point B, one trip is $4,000. If it's five cops, you're talking $20,000.

``If we offered enough, they used their police uniforms and their patrol cars to protect that load.''

Law enforcement authorities say while it's likely that most drug dealers here have a police officer on the payroll, the corruption does not appear to be organized or to reach police brass.

Police Association President José Rodríguez said ''98 percent'' of police officers were honest, and that the department leadership publicizes isolated corruption cases in order to cover up its lack of progress in the fight against crime.

''There are corrupt police in Puerto Rico, but not as much as other cities in the United States,'' Rodríguez said. ``These cases are not so frequent, despite our low pay. We are the lowest paid police officers in the entire country.''

Officers make about $26,400 a year, said Rodríguez, a police captain in Carolina, a municipality near San Juan. He added that in Puerto Rico, sergeants supervise 35 to 30 patrol officers, compared to an average of 10 in the United States.

''It's impossible to have effective control,'' he said.

Toledo said the island's police department plans to raise the minimum hiring age from 18 to 21 and beef up its screening process to include polygraphs. But he and other authorities agreed that to stop corrupt police, they have to stop drug trafficking. And to do that, they must largely rely on federal agencies because local police are prohibited by law from tapping phone lines, using body recorders or holding suspects without bail.

U.S. Attorney Rosa Emilia Rodríguez-Vélez said her office has lowered the threshold for the cases federal prosecutors will take. Her office now regularly files gun possession charges and drug cases for low quantities of cocaine in the quest to crack down on street-level drug peddlers.

''I was local assistant D.A. for 10 years. I got to know a lot of officers; their commitment is extraordinary,'' she said. ``The vast majority -- vast majority -- are good, decent officers. This is not an indictment of the police force. It's an indictment against members who misuse their positions.''

CRIME REDUCTION

Law enforcement agencies have formed joint strike forces, which are beginning to show reductions in crime in the pilot cities where they were launched.

''The issue is not the police. The issue is drug trafficking,'' she said. ``We have a drug trafficking problem and a violent crime problem. The murder rate is very high.''

In 2006, 736 people were murdered in Puerto Rico, a rate about three times higher than the U.S. mainland's average. By July 15 of this year, 365 people had been murdered.

The year started out with an explosion of violence attributed to a power vacuum left when notorious drug trafficker José ''Coquito'' López Rosario was gunned down last summer, and the rival dealer who allegedly ordered him killed, Alex Trujillo was finally captured.

When López Rosario was killed, authorities began investigating his ties to three local senators, one of whom brought López along on a series of prison inspections. Although he was arrested many times, his cases always fell apart in court, said Sergio Rubio Paredes, head of the Puerto Rico Justice Department's organized crime division.

A justice department top prosecutor lost his job when accused of accepting a Mercedes Benz from López. Although he was cleared of wrongdoing, his contract was not renewed.

''Coquito had a lot of connections,'' Toledo said, ``including judges.''

López had friends in the police department, too, the superintendent said: His mom provided free catering to police holiday parties.

''We need to attack the roots of the problem,'' Rubio said. ``In Puerto Rico, we have proven that hiring more police does not work.''