The curious case of Macho B, the jaguar captured in southern Arizona, has quickly descended into finger pointing and official investigations.

There are questions about whether the jaguar was euthanized too quickly, as well as accusations he was captured on purpose, not accidentally, as the Arizona Game and Fish Department has stated.

On Thursday, the U.S. Fish and Wildlife Service said its law-enforcement division had begun a criminal investigation into all aspects of the capture and death of the animal.

It began its investigation after a request from U.S. Rep. Raul Grijalva and because Game and Fish asked for an outside agency to look into what happened.

Already, the complicated legacy of the jaguar's capture and death stands in stark contrast to the simplicity of his life, when he roamed northern Mexico and southern Arizona for 15 years.

The jaguar, an endangered species, was captured on Feb. 18 by a team led by the Arizona Game and Fish Department.

From the very beginning, Game and Fish said the capture was inadvertent.

The agency said it was trapping as part of a years-long study of other large mammals in a remote section of the Coronado National Forest west of Nogales.

Once a jaguar was captured, Game and Fish decided the opportunity to learn more about the elusive animal was so compelling that Macho B was sedated, fitted with a satellite radio transmitter, and released.

Jose Viramontes, of the U.S. Fish and Wildlife's regional office in New Mexico, said Arizona Game and Fish had the necessary permits to capture an endangered species as long as it was part of conservation efforts.

Macho B's radio collar would broadcast his location every three hours. After just a few days, however, those signals indicated trouble. The cat was not moving as it should.

On March 2, Macho B was found, tranquilized again, and flown by helicopter to Phoenix Zoo.

Hours later, zoo veterinarians decided the cat was suffering acute kidney failure and advised officials from Game and Fish and the U.S. Fish and Wildlife Service that Macho B should be euthanized.

In recent days, however, there have been questions about the jaguar's treatment.

Macho B was very old for a wild animal, but when he was captured on Feb. 18, Game and Fish described him as "thick and solid."

They went on to add that "field biologists' assessment shows the cat appeared to be healthy and hardy."

But 12 days later, he was said to have "off-the-charts kidney failure."

After Macho B's death, some of his tissues were sent to the University of Arizona's veterinary diagnostics laboratory.

One of the pathologists there, Dr. Sharon Dial, said Macho B's kidneys were not in chronic failure. They were, in fact, fairly healthy.

She contended that Macho B may have been put down too soon.

Arizona Game and Fish pilloried her.

Her comments, the department said in a statement, were "outrageous, unprofessional and speculative."

Dial regretted that she may have put her lab in a "difficult position." But she is not backing down from her assertions.

"The kidneys did look good," Dial said.

One of the veterinarians who treated Macho B at the zoo, and who made the recommendation that he be put down, said he stands by his decision.

"He was in kidney trouble, big time," Dr. Dean Rice said. "His (kidney function) readings weren't high, they were off the scale. It didn't matter if it was acute or chronic."

Rice said that people who question if Macho B was put down too soon are forgetting the animal.

"The question becomes: How do you treat this animal? Keep him sedated for days? That's no good. You wake him up, you knock him down. You wake him up, you knock him down. That's not good for the cat. It would be tough for a zoo animal, and this was a wild animal."

Rice said if given the chance, he would treat the animal the same way.

"He was in very serious trouble," Rice said. "I think it was virtually impossible to treat him."

Grijalva wants all aspects of the animal's capture and death investigated, including whether the animal was targeted for capture by Game and Fish.

His request may stem in part from startling accusations about the capture of Macho B. A woman directly involved in the capture said it was no accident.

Janay Brun, working with Game and Fish as a member of the Borderlands Jaguar Detection Project, told the Arizona Daily Star that she baited the trap that caught Macho B with jaguar scat as part of an effort to capture a jaguar and now regrets it.

"That jaguar meant a lot to me, and the fact that I mindlessly participated in this, it's a regret I'll have for the rest of my life," Brun told the Tucson paper.

Arizona Game and Fish vigorously denies her accusations.

Larry Voyles, the director of the department, said the jaguar was captured during a study of black bears and mountain lions.

"We knew there was the potential to ensnare a jaguar," Voyles said. "That was not the purpose or intent."

Voyles said that once the animal was ensnared, his agency needed to sedate it.

"You must tranquilize the animal to remove (the snare). That's the hard part. Putting a collar on it is easy," Voyles said. "To fail to put the collar on it, with very little additional risk, would be irresponsible."

The agency did have a plan in case it captured a jaguar, but that is not the same as planning to capture a jaguar, according to Voyles.

"We had a duty to be prepared," he said.

The necropsy of Macho B is ongoing at different locations. The data will be reviewed by Dr. Linda Munson, a veterinary pathologist and big-cat expert at the University of California - Davis School of Veterinary Medicine.

Viramontes said his agency will look at all aspects of what happened but "could not comment on the specifics."

Voyles defended Arizona Game and Fish. He said that based on the information he has, and unless an investigation yields new facts, he would do nothing different.

"Not that I can think of," Voyles said. And then he paused. "We wish the whole circumstance had not occurred."