The incident took place during a US operation against the powerful criminal organization, the Department of Justice has revealed

A hacker working for Mexico's most powerful drug cartel accessed the phone records and geolocation data of a senior FBI agent assigned to the US Embassy in the country, according to the latest report by the US Department of Justice (DOJ) Office of the Inspector General.

The incident took place in 2018, when the FBI was working on a high-profile case gathering evidence against notorious Mexican drug lord Joaquin Guzman Loera, nicknamed "El Chapo," the longtime leader of the Sinaloa cartel.

The cyber operative hired by the gang also managed to tap into Mexico city's CCTV network, allowing the cartel to monitor the agent's movements and identify individuals he met with, some of whom were later intimidated or killed, the report stated.

Under Guzman's leadership, the Sinaloa cartel became the main supplier of drugs to the US, trafficking vast quantities of cocaine, heroin, methamphetamines, and marijuana.

Guzman was arrested in Mexico in 2016 and extradited to the US. In 2019, a federal court in Brooklyn sentenced him to life in prison plus 30 years. He is now serving his sentence in ADX Florence, the most secure federal prison in the US.

His capture did not bring an end to the cartel; power shifting to other leaders and the flow of drugs north has continued unabated.

Recent advances in surveillance technology and their availability to criminal groups and "less-sophisticated nations" are now viewed as an "existential" threat by US intelligence agencies like the FBI and CIA, the DOJ report stated.

After returning to office in January, US President Donald Trump has taken a hardline approach toward Mexico's role in the drug trade.

In one of his first moves, he designated several Mexican cartels, including the Sinaloa Cartel, as Foreign Terrorist Organizations - a move that could open the door to expanded military or intelligence operations.

Last week, the US Treasury Department imposed sanctions on three Mexican financial institutions accused of laundering cartel money, presumably cutting them off from the American financial system.

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Trump has also floated the possibility of missile strikes on cartel drug labs inside Mexico. Meanwhile, the CIA is reportedly conducting drone surveillance missions deep into Mexican territory to monitor cartel operations.

The policies have strained US-Mexico relations. Mexican President Claudia Sheinbaum has criticized the lack of evidence behind some of Washington's actions and warned against violating the country's sovereignty.