A villa in Kabul where members of a Pentagon task force designed to bolster business allegedly lived. (Source: SIGAR)

Government investigators are widening their probe in to a now-defunct task force in Afghanistan that allegedly spent $43 million to build a single gas station, by probing allegations that it spent $150 million, or nearly 20 percent of its budget, on private housing and security.

In a letter to Defense Secretary Ashton Carter, John Sopko, the Special Inspector General for Afghanistan Reconstruction, questioned the costs, saying that it would have been far more efficient to live on U.S. military bases instead.

Those facilities routinely provide “housing, security and feed service,” he wrote. If the staff lived there instead of in private villas, “it appears the taxpayers would have saved tens of millions of dollars.”

[How the Pentagon spent $43 million on a single Afghan gas station]

Sopko’s letter quoted a former defense official who said that the Task Force for Stability and Business Operations expressly avoided staying on military bases because “the goal was to show private companies that they could set up operations in Afghanistan themselves without needing military support.”

In a statement, Sen. Charles E. Grassley (R-Iowa) said he wasn’t buying that: “The assertion that task force employees had to have outside housing and security to set an example for private companies sounds like U.S. Grade A baloney.”

Sopko’s letter said the task force spent $57 million for armed support between 2010 and 2014. Private contractors also provide task force personnel with a variety of comforts, including “queen sized beds in certain rooms,” and in each room a flat screen TV that was 27 inches or larger, a DVD player and a mini refrigerator.

The food had to be “at least 3 stars,” Sopko’s letter said, “with each meal containing at least two entrée choices and three side order choices, as well as three course meals for ‘special events.’ ”

Earlier this month, Sopko released a report into how the task force spent $43 million on a compressed natural gas station in Afghanistan when a similar one built in Pakistan cost about $500,000. Grassley’s office has said there is an ongoing criminal investigations into the task force.

“Everybody responsible for the tremendous waste of U.S. tax dollars on the gas station and any other projects ought to be held accountable,” Grassley said in a statement.