One particular lowlight: On Aug. 21, 2011, police reports indicate, officers were summoned to a Loquat Avenue cottage owned by another brother. He sometimes stayed at the Coconut Grove dwelling while off-duty. Earp had pulled out an AK47 and begun firing.

He claimed he was shooting at a man who had first shot at him after Earp caught the interloper breaking into his Land Rover.

Earp appeared to be drunk, according to the police report, and investigators became skeptical when the agent had trouble keeping his story straight.

One of his IRS bosses arrived at the scene and took Earp’s weapons.

Feeling the heat

It was not the first time Earp felt threatened by enemies real or trumped up in his mind. His brother said it was hard to figure out whether his brother was buckling under agency pressure or whether someone in the criminal underworld really was trying to get him.

Around then, Earp reached out to Miami attorney Steven M. Harris, who said the agent definitely felt he was being wronged by his employer.

Harris said Earp, who earned $135,000 a year and had a daughter in college, feared he would be forced out of the agency before getting all the pension benefits he hoped to earn.

Earp’s former boss, Anthony Falcone, now retired from the IRS, said he had heard that Earp was having trouble with his bosses and that they were giving him a hard time.

“[When] Patrick worked for me … I never saw any discrepancies with what he was doing,” Falcone said. “There was a lot of stress on him. Yes, he was involved in some things with the agency, but he was getting ready to retire. He worked in the Keys, which is not for everybody.’’

Said another retired agent and former colleague, who asked to remain anonymous: “There were people within the agency who didn’t understand what we did in our undercover work. Some of them were educated paper-pushers who thought we were cowboyish.’’

In the months before his death, Earp was reassigned to a desk job in Miami. After more than a decade of working on his own, sitting in an office made him miserable, feeling like the agency put him out to pasture. His health suffered, and he began drinking heavily and taking Xanax, a drug to treat anxiety and panic attacks. His relationship with Londono deteriorated.

In November 2011, Earp checked into rehab, his brother and girlfriend said. Upon his release, suffering from vertigo and drinking anew, he briefly moved back in with his wife in an attempt to reconcile.

Ted Clausen, a fellow agent with whom he was close, said Earp was facing a lot of challenges. Despite the warning signs, few in the agency seemed to notice working undercover for so many years had taken such a toll on the veteran agent.

“I knew him, like, for 10-15 years. If I would have known this would have been the final outcome, I would have said something to someone. But how do you know? Everybody goes through problems and they come out of it,’’ Clausen said.

Rob Earp said his brother “felt as if his honor and integrity were destroyed, and these were the two qualities he lived by. And by far the worst part of his ordeal was the way he felt his organization had abandoned him and humiliated and questioned his character and assigned him to meaningless tasks.”

Lingering doubts

For months after Earp’s death, his brother suspected he may have been murdered. There was no suicide note, no squaring of accounts, nothing to indicate his state of mind. A lifelong Catholic, Earp had vowed that he would never take his life.