(CNN)Leonard Francis, the former military contractor known as “Fat Leonard” who orchestrated the largest corruption scandal in US Navy history, is on the run after escaping house arrest in San Diego by cutting off his GPS monitoring ankle bracelet, according to the US Marshals Service.

The escape, first reported by The San Diego Union-Tribune, comes just three weeks before his sentencing.

The federal agency monitoring Francis' house arrest, Pretrial Services, called the San Diego Police Department on Sunday to check on him, Supervisory Deputy US Marshal Omar Castillo told CNN. When police discovered Francis' home empty, they contacted the US Marshals, Castillo said.

When a team of US Marshals went to Francis' house on Sunday, Castillo said, the only thing they found was the ankle bracelet he had cut off and left in a portable cooler.

Neighbors told the US Marshals that they had recently seen several U-Haul trucks at Francis' house, according to Castillo.

“It appears he has been planning this for a while,” he told CNN.

The Pacific Southwest Regional Fugitive Task Force, San Diego division -- which is run by the US Marshals -- is searching for Francis.

Castillo said the Naval Criminal Investigative Service (NCIS) is also involved because they worked on the original case.

“We have a few leads we're following,” Castillo said.

The US Marshals Service has issued a nationwide “be on the lookout” alert for Francis, Castillo told CNN Tuesday afternoon.

The former military contractor has been flagged as a fugitive in a nationwide database used by law enforcement during police encounters, Castillo said, which will also alert US Marshals in the event Francis attempts to board a flight under his name in any commercial airport in the country.

The US Marshals Service is also coordinating with its border control and law enforcement counterparts in Mexico if Francis attempts to flee via the US southern border, he added.

Kelly Thornton, with the US attorney's office in the Southern District of California, told CNN on Tuesday that her office “is supporting the U.S. Marshals Service and its San Diego Fugitive Task Force in their efforts” but declined to comment further.

Francis, whose nickname came from his then 400-pound heft, pleaded guilty to bribery and fraud charges in 2015.

The investigation into the corruption scandal began in 2013 and touched on capitals and ports across the Pacific, including Singapore, Tokyo, Bangkok and Manila. During the probe, multiple Navy officials were arrested and accused of accepting cash, prostitutes and all-expenses-paid trips in exchange for steering ships to ports where Francis' contracting company operated, providing services such as fuel and tugboats.

CNN has reached out to the FBI in San Diego. When contacted by the San Diego Union-Tribune Monday, Francis' defense attorney declined to comment. (CNN)

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