Hunter Biden appeared to receive help from his father on several occasions as he pursued business deals in Mexico during the last few years of Joe Biden’s vice presidency, according to House Repiblicans.

The complicated business ventures included an effort by Burisma, a Ukrainian energy company that paid Hunter Biden for a board position, to buy up parts of a Mexican-owned energy conglomerate that was looking to privatize.

The Mexican ventures have received less attention than Hunter Biden’s work in Ukraine and China, in large part because it’s unclear if the largest deals came to fruition or ever netted Hunter Biden and his business partners significant earnings.

But while lucrative opportunities in Mexico were on the table, Hunter Biden seemingly relied on the trappings of his father’s vice presidency to advance his Mexican business interests.

Joe Biden’s involvement in his son’s businesses has landed at the heart of House Republicans’ impeachment inquiry, which will see its first hearing on Thursday.

Hunter Biden and his business associates appeared to be interested in targeting Mexican investors since at least 2010. Among them were Carlos Slim and his son, Carlos Slim Jr.; the elder Slim, a Mexican billionaire, was at one point the wealthiest man in the world.

Miguel Aleman Velasco and Miguel Aleman Magnani also appeared to develop close business relationships with Hunter Biden and his business partners, particularly Jeff Cooper, one of Hunter Biden’s closest business associates at that time. Aleman Velasco was a former high-ranking Mexican politician, and his son, Aleman Magnani, was the president of Interjet, at the time a Mexican airline.

Hunter Biden, Cooper, and their former business partner, Devon Archer, appeared to lean on Aleman Magnani to help them explore business opportunities in Mexico, including how to profit off the privatization of Pemex, a state-owned oil and gas company in Mexico. Burisma appeared interested in bidding on assets that Pemex was preparing to sell.

In February 2014, Hunter Biden and Cooper arranged a lunch with then-Vice President Joe Biden at the White House, emails from Hunter Biden’s abandoned laptop show.

Joe Biden met with both Aleman Velasco and Aleman Magnani, along with Cooper, at the White House for lunch and posed for pictures with them.

Later, Cooper and Hunter Biden discussed sending prints of the photos signed by Joe Biden to Aleman Velasco and Aleman Magnani.

In March 2014, Hunter Biden planned to call then-Transportation Secretary Anthony Foxx, who had set up a meeting with Aleman Magnani, the Mexican airline executive, to let Foxx know that he and Aleman Magnani were “buddies.”

Aleman Magnani appeared to help Hunter Biden and his associates make connections at Pemex and in the Mexican government.

As Burisma got more serious about an investment in Mexico, executives at the Ukrainian energy company asked Hunter Biden for his help in securing a visa for Mykola Zlochevsky, the head of Burisma, to travel to Mexico without issue.

Zlochevsky’s U.S. visa was suspended at the time, and the group feared Mexican authorities would deny his entry because of that.

Hunter Biden turned to Aleman Magnani for help with the visa issue.

In February 2015, Aleman Magnani pushed back the timeline for a deal involving Burisma and Hunter Biden’s business partners, threatening the arrangement.

Cooper attempted to reassure a worried Hunter Biden that Aleman Magnani and his father “clearly value the relationship with your family.” Cooper then suggested having Joe Biden call Aleman Velasco to smooth things over.

“Maybe a call from your or your dad to his dad? Maybe that shakes things loose?” Cooper wrote in an email.

It’s unclear if Joe Biden made any calls to advance the deal at that time.

But by March 2015, Aleman Magnani appeared to have made a $1 million investment in a business in which Hunter Biden had a small stake. Separate from the Pemex deal involving Burisma, Cooper and Hunter Biden had been pushing for the expansion of the other company, ePlata, in Mexico.

Hunter Biden received a $50,000 wire transfer as a result of the Aleman Magnani investment.

That same month, Hunter Biden and his then-wife Kathleen went to stay at Aleman Magnani’s house in Acapulco, Mexico, and had plans to be brought back to the United States on Aleman Magnani’s private jet.

As he worked with Miguel Aleman later in March 2015 to set up a meeting with Slim and Slim Jr., Hunter Biden mentioned that he’d shown his father pictures of the Acapulco trip and that Joe Biden had said he wanted to visit as well.

Hunter Biden was not the only Biden family member looking to get into business with Slim and Pemex.

James Biden, Joe Biden’s brother, emailed Hunter Biden in May 2015 to gauge his interest in getting involved in his separate dealings with Slim and the Mexican oil conglomerate.

Hunter Biden and his associates appeared to maintain interest in doing business in Mexico into late 2015 and 2016.

Hunter Biden appeared to coordinate a call or meeting with Slim and Joe Biden’s government office for Oct. 30, 2015, emails show.

He and his business partners appeared to be in regular contact with Slim at that time.

In February 2016, Joe Biden brought Hunter Biden and Cooper to Mexico with him on Air Force Two.

It’s unclear whether Joe Biden met any of their Mexican business associates on that trip, but the fact that he traveled with Cooper and his son to Mexico while they were working on deals in that country could raise red flags for congressional investigators.

The House Oversight Committee sent a letter to the National Archives on Aug. 30 demanding any records related to Air Force Two trips taken by Hunter Biden, Archer, Cooper, or another of their former business partners, Eric Schwerin, while Joe Biden was vice president.

House Oversight Republicans will lead their first impeachment inquiry hearing on Thursday, where they plan to lay out the rationale for pursuing the inquiry.