WASHINGTON — When President Donald Trump’s administration last month awarded a contract worth up to $1.2 billion to build and operate what it says will become the nation’s largest immigration detention complex, it didn’t turn to a large government contractor or even a firm that specializes in private prisons.

Instead, it handed the project on a military base to Acquisition Logistics LLC, a small business that has no listed experience running a correction facility and had never won a federal contract worth more than $16 million. The company also lacks a functioning website and lists as its address a modest home in suburban Virginia owned by a 77-year-old retired Navy flight officer.

The mystery over the award only deepened last week as the new facility began to accept its first detainees. The Pentagon has refused to release the contract or explain why it selected Acquisition Logistics over a dozen other bidders to build the massive tent camp at Fort Bliss in West Texas. At least one competitor has filed a complaint.

The secretive — and brisk — contracting process is emblematic, experts said, of the government’s broader rush to fulfill the Republican president’s pledge to arrest and deport an estimated 10 million migrants living in the U.S. without permanent legal status. As part of that push, the government is turning increasingly to the military to handle tasks that had traditionally been left to civilian agencies.

A member of Congress who recently toured the camp said she was concerned that such a small and inexperienced firm had been entrusted to build and run a facility expected to house up to 5,000 migrants.

“It’s far too easy for standards to slip,” said Rep. Veronica Escobar, a Democrat whose district includes Fort Bliss. “Private facilities far too frequently operate with a profit margin in mind as opposed to a governmental facility.”

Attorney Joshua Schnell, who specializes in federal contracting law, said he was troubled that the Trump administration has provided so little information about the facility.

“The lack of transparency about this contract leads to legitimate questions about why the Army would award such a large contract to a company without a website or any other publicly available information demonstrating its ability to perform such a complicated project,” he said.

Ken A. Wagner, the president and CEO of Acquisition Logistics, did not respond to phone messages or emails. No one answered the door at his three-bedroom house listed as his company’s headquarters. Virginia records list Wagner as an owner of the business, though it’s unclear whether he might have partners.

Defense Secretary Pete Hegseth approved using Fort Bliss for the new detention center, and the administration has hopes to build more at other bases. A spokesperson for the Army declined to discuss its deal with Acquisition Logistics or reveal details about the camp’s construction, citing the litigation over the company’s qualifications.

The Department of Homeland Security, which includes U.S. Immigration and Customs Enforcement, declined for three weeks to answer questions about the detention camp it oversees. After this story was published Thursday, the department’s spokeswoman, Tricia McLaughlin, issued a statement that said “under President Trump’s leadership, we are working at turbo speed on cost-effective and innovative ways to deliver on the American people’s mandate for mass deportations of criminal illegal aliens.”

She said the Fort Bliss facility “will offer everything a traditional ICE detention facility offers, including access to legal representation and a law library, access to visitation, recreational space, medical treatment space and nutritionally balanced meals.”

Named Camp East Montana for the closest road, the facility is being built in the sand and scrub Chihuahuan Desert, where summertime temperatures can exceed 100 degrees Fahrenheit and heat-related deaths are common. The 60-acre site is near the U.S.-Mexico border and the El Paso International Airport, a key hub for deportation flights.

The camp has drawn comparisons to “Alligator Alcatraz,” a $245 million tent complex erected to hold ICE detainees in the Florida Everglades. That facility has been the subject of complaints about unsanitary conditions and lawsuits. A federal judge recently ordered that facility to be shut down.

The vast majority of the roughly 57,000 migrants detained by ICE are housed at private prisons operated by companies like Florida’s Geo Group and Tennessee-based CoreCivic. As those facilities fill up, ICE is also exploring temporary options at military bases in California, New York and Utah.