In 2007-08, he worked a case called “Operation Tarnished Blue,” targeting the distribution of cocaine, crack and heroin in Florida City and Homestead.

The head of the organization, who allegedly enjoyed police protection, purportedly operated several heroin and cocaine houses in Miami-Dade’s southernmost cities from which he and his cohorts generated thousands of dollars a day in narcotics sales. HIDTA tracked the drug trail to Miami and to temporary stash houses in South Dade, one of which was called the “Stump,” located in the Goulds area.

From there, the trail went to North Florida and to points as far north as Detroit.

Earp received good evaluations from his bosses. He traveled around the country while living most of the time in a waterfront Key Largo condo under the name Murphy. His case files, perused by The Herald, indicated he built a number of successful cases leading to convictions.

But for Earp, life began to unravel when, in April 2009, he was accused of mismanaging about $15,000 in government funds, known as Imprest Funds. In this case, it was money budgeted to cover the cost of storing and operating the vessels he bought with government money in the course of his undercover work, confidential government memos indicate.

Earp was scolded for using his personal credit cards to pay for docking fees, and for failing to properly expense the storage fees.

Nobody accused him of stealing, and Earp, who was meticulous about documenting his expenses, was ultimately able to provide all the necessary receipts, according to documents and emails reviewed by The Herald. But the ordeal was a slap in the face to Earp, who friends and family say was a loyal company man.

“There was some funds and they tried to blame the problem on him … He found out about this by accident, and the end result was a top commander and his immediate boss were gone right after he brought it to their attention,’’ Rob Earp said.

Michael Dobzinski, spokesman for the IRS in Florida, declined to comment for this story.

Sleeping with guns

Around that same time, Patrick Earp lodged an internal affairs complaint, alleging wrongdoing by his bosses in the IRS. He told family and friends that the problem went up to the highest levels of the agency. The files inspected by The Herald show no evidence of that wrongdoing.

Earp, estranged from his wife for 2 1/2 years, lived at the time with a girlfriend, Sandra Londono. She asserts that after that complaint was made, she received two anonymous, threatening messages on her phone, which she reported to authorities. She said Earp gave her his computer for safekeeping, telling her to turn it over to IRS investigators only if something happened to him, which she did.

Both began sleeping with guns. Though Earp always looked over his shoulder for the shadowy characters he tried to send to jail, he now became fearful that others closer to home were trying to silence him, Londono said.

“He was more scared of his agency than anyone else,’’ Londono said.

From that time on, Earp’s life became increasingly difficult. After the better part of a decade embedded in the Keys, Earp had become steeped in its boozy, laid-back culture, using his assignment as a seaside escape from his marital and work problems.

He began a mental and physical downward spiral, fueled by alcohol, pills and job stress, Londono and Rob Earp said.