People walk past graffiti along the border structure in Tijuana, Mexico, in January. (Julie Watson/AP)

A Hispanic-owned firm whose workers have been threatened and harassed for security projects along the Mexico border was chosen Thursday to build a prototype for President Trump's long-promised border wall.

The company was among four companies selected by U.S. Customs and Border Protection Thursday to build the see-through prototypes. In addition to the Hispanic-owned KWR Construction of Sierra Vista, Ariz., the winners are: Caddell Construction in Montgomery, Ala.; ELTA North America in Annapolis Junction, Md.; and W.G. Yates & Sons Construction in Philadelphia, Miss.

Each of the contracts is worth between $300,000 and $500,000. Caddell and Yates & Sons also won separate contracts to build concrete prototypes, the agency announced last week.

Al Anderson, the general manager of KWR Construction, which had helped build portions of the existing border fence as well as associated roads and lighting, would not divulge design details of its prototype for the contentious border project. Under the contract terms, the firms had to use materials other than concrete.

“We want whatever jobs here along the border that we can get, and set aside our personal beliefs to support our employees,” Anderson said in a previous interview with The Washington Post. “We are going to make lemonade from this lemon.”

Trump this summer had repeatedly promoted a border wall made of solar panels, but the agency would not confirm Thursday whether it had selected such a design. Representatives for Caddell, ELTA and Yates & Sons did not immediately return requests for comment on their design concepts.

ELTA is a defense manufacturer owned by the state-run Israel Aerospace Industries. The parent company is under investigation for bid rigging and bribery, according to Haaretz. ELTA, which makes radars, opened new U.S. headquarters in Maryland in May.

Construction on the prototypes is expected to begin in San Diego this fall, although no money has been appropriated to pay for Trump’s pet project and key campaign promise of building a wall spanning the entire 2,000-mile U.S.-Mexico border. Congress has set aside only $20 million in the current budget to plan for and build the prototypes. That amount includes money for architecture and engineering support for real estate, environmental and wall design efforts.

Anderson had previously told The Post that Mexicans would harass his workers in profanity-laced Spanish and throw rocks over a fence as they installed lighting during previous work on the border. One of his employees so feared for his life that he donned a bulletproof vest at work every day. Anderson said he expects the harassment to get worse and that some of his construction workers, who he called “conscientious objectors,” would quit.

“It was a rough environment, and I expect it to be more charged now than it has been in the history of working along the border,” Anderson said in March. “Not only are Mexicans infuriated with the United States, but people in the United States are also infuriated.”

Arthur Rivas, president of KWR, said in a written statement to The Post on Thursday that “many of our workers have long-standing relations or roots in Mexico, so all of us respect our Mexican neighbors and have a good sense of where they're coming from.” He acknowledged that “fencing isn't a perfect solution,” but if it becomes inevitable, “it might as well be built well, and by us.”

Trump, just days after he was inaugurated in January, issued an executive order directing the Department of Homeland Security to “immediately plan, design and construct a physical wall along the southern border.”

On Tuesday, Trump, who campaigned on border security and the deportation of illegal immigrants, canceled an Obama-era program that had allowed 800,000 undocumented immigrants who arrived in the United States as children to live and work in this country without fear of deportation.

Trump said he is phasing out the Deferred Action for Childhood Arrivals (DACA) program to allow Congress six months to come up with a legislative solution. Some congressional Republicans are expected to use DACA as a bargaining chip to fund the border wall, which Democrats firmly oppose.  

Trump’s 2018 budget calls for $2.6 billion for “high-priority tactical infrastructure and border security technology.” Of that amount, $1.6 billion is for “bricks and mortar construction” and $1 billion is for infrastructure and technology, such as roads needed to access construction sites and surveillance equipment.

Trump had earlier threatened to shut down the government if a budget deal did not include funding for the border wall, but he pulled back on the threat last week.

Opponents of the wall argue that it’s unnecessary, given that there is already nearly 700 miles of fencing along the most critical areas of the border, and that illegal crossings have decreased.

Trump has acknowledged that a seamless wall would not be possible, nor practical, given natural barriers in the landscape as well as international treaty and flood-zone requirements.

The government in March asked for design submissions for two types of a wall: a reinforced concrete barrier wall and one made of an alternative material with see-through capability. The wall, between 18 and 30 feet high, must be insurmountable and “aesthetically pleasing in color,” at least from the U.S. side, according to the design specifications. It must also withstand digging for at least six feet below the surface.

More than 200 companies responded with proposals. The contenders were winnowed down to a secret list of about 20 finalists.

Thursday’s announcement follows last week’s awarding of four contracts for concrete prototypes. The earlier winners were: Fisher Sand & Gravel/DBA Fisher Industries of Tempe, Ariz., and Texas Sterling Construction in Houston, along with Caddell and Yates & Sons.

Alice Crites contributed to this report.