The federal grand jury probe that led to the raid of Democratic Congressman Henry Cuellar's home and office in Texas this week has begun issuing subpoenas, seeking records about a wide array of U.S. companies and advocacy organizations, many of them with ties to the former Soviet nation of Azerbaijan.
Among the information being sought, according to one subpoena reviewed by ABC News, are records related to the congressman, his wife Imelda, and at least one of his campaign staffers.
An attorney representing Cuellar, Joshua Berman, told ABC News that "the congressman and his family are fully cooperating" with the investigation. On Wednesday, after the FBI raids in Laredo, Texas, an aide to Cuellar said the congressman is "committed to ensuring that justice and the law are upheld."
The subpoenas issued in recent days came from a federal grand jury in Washington, D.C.
The FBI and Justice Department have declined to discuss the investigation or describe its scope.
It is unclear if Cuellar or his wife are targets of the probe. But, in addition to other information, the subpoena reviewed by ABC News seeks records "relating to anything of value" that the congressman, his wife, and others close to them may have been offered by certain business leaders or foreign officials.
The subpoena also asks for records relating to any "work, act, favor, or service" that Cuellar or his wife may have provided at the behest of certain foreign companies, government officials, American business leaders, or others.
The subpoena reviewed by ABC News specifically seeks records related to at least three Texas-based companies for which online databases identify Imelda Cuellar as an officer or director. It also seeks records relating to an array of logistics-related firms and cultural advocacy organizations from around the United States, many of them with ties to Azerbaijan, which sits on the Caspian Sea near Iran, Russia and Georgia.
Touting Azerbaijan as "a secular, modern, Muslim country," Cuellar has been an outspoken advocate for the nation over the past decade, even serving as a co-chair of the Congressional Azerbaijan Caucus.
He publicly called Azerbaijan "a strong ally of the United States" and a key partner in "the global war on terrorism," noting that -- in the wake of the Sept. 11, 2001, attacks -- it provided an important route for sending reinforcements and supplies to American forces in Afghanistan.
On the House floor last year, Cuellar offered remarks to "honor the diplomatic tour" of Azerbaijan's long-serving ambassador to the United States, Elin Suleymanov, describing Suleymanov as "a force of peace and diplomacy."
In recent years, Cuellar and Suleymanov attended many of the same events, including the 2015 announcement of what Cuellar called an "historic agreement" between Laredo's Texas A&M International University and the government of Azerbaijan.
That agreement established an annual two-week program for Laredo-area college students to visit Azerbaijan and learn about international energy issues, including the worldwide oil and gas industry, according to press releases from Cuellar's office.
The "Baku Summer Energy School" program was backed by a partnership between ExxonMobil, the Azerbaijan Diplomatic Academy in Baku, Azerbaijan's capital, and the nation's state-owned gas company, known as SOCAR, according to the press releases.
In 2015, when the first iteration of the program was announced, the Turkish-born head of a local nonprofit that also helped arrange the program, Kemal Oksuz, issued a statement thanking Cuellar "for his playing a very instrumental role" in making it all happen.
Three years later, in 2018, federal authorities arrested Oksuz for his role in a scheme to conceal that a 2013 congressional delegation to Baku -- which did not include Cuellar, according to press reports -- was paid for by SOCAR, the state-owned gas company, "in order to gain access to these public officials," the Justice Department said.
Oksuz admitted to lying on U.S. disclosure forms, pleading guilty to one scheme-based count, and was sentenced to time served. But his lawyers insisted that he "never attempted to corrupt any action by a government official, and never would have agreed to participate in such an effort."
The subpoena reviewed by ABC News is seeking, among other information, records related to Oksuz, SOCAR, the Azerbaijan Diplomatic Academy, and other entities that the Justice Department mentioned in its case against Oksuz.
Cuellar, who represents Texas' 28th Congressional District along the U.S.-Mexico border, has been in Congress since 2005.
Cuellar is in the final weeks of a tough reelection campaign. He faces a challenge for his seat from a fellow Democrat, and the primary election is being held on March 1.
The Justice Department usually tries to refrain from taking overt investigative steps involving a candidate close to an election.
A Justice Department spokesman declined to comment for this story.
ABC News' Benjamin Siegel contributed to this report.