A Mexican college student admitted Wednesday that he smuggled large loads of drug cash through San Antonio until he and a friend were caught trying to fly from the Alamo City with nearly $1 million last summer.

No one knows for sure yet how much Rafael Gabriel Martinez Leal, now 21, smuggled into Mexico during the first seven months of 2018, but according to new evidence revealed in court Monday, he admitted making trips with $300,000 in cash or larger.

Related: Monterrey teen, accused of smuggling $900,000 cash via San Antonio plane, opts to stay in jail

His final load was intercepted as he and some of his socialite friends, including Juan Pablo Hoyos Avila, 19, a former student at the University of the Incarnate Word who was charged with him, were about to take off in a plane bound for Monterrey on July 15, 2018.

Someone had tipped off federal agents about a large amount of cash on the aircraft, and the plane was diverted for inspection by customs agents, U.S. District Judge Fred Biery said, reading from Martinez’s plea deal.

During the inspection, agents asked the plane’s five occupants, including the pilot, if they had anything over $10,000 to declare, court records said. Hoyos declared $960.

A federal affidavit said eight sealed boxes that had pictures of a fan and one fan that was not in a box were found inside the plane. Seven of the boxes contained bundles wrapped in gray duct tape.

Related: S.A. student and friend accused of smuggling nearly $1 million hit with new charge

The bundles were opened and U.S. currency totaling $879,099 was found. Another $30,000 in cash was found in Martinez’s luggage, Biery said, reading from the plea deal.

Hoyos is scheduled to go to trial next month on charges of money laundering conspiracy and bulk cash smuggling.

Martinez pleaded guilty to conspiracy to launder money. He faces up to 20 years in prison. Sentencing is set for Nov. 5.

The three other passengers, including a pilot who told agents he had flown Martinez three times from San Antonio, were not charged and were allowed to leave.

“He took responsibility for what he did,” Martinez’s lawyer, Steven Redgate, said after Monday’s hearing. “He knew it was wrong.”

Martinez is the cousin of two prominent people in the northern Mexican state of Tamaulipas —Mariana Gómez de García Cabeza de Vaca, the wife of the governor, Francisco Garcia Cabeza de Vaca, and of José Ramón Gomez Leal, a top official in Tamaulipas for Mexico's president, Andres Manuel López Obrador.

The governor has acknowledged Martinez is his wife’s cousin, but said he knew nothing of Martinez’s alleged illicit activities, and that Martinez should pay for his crime if he is found guilty.

On ExpressNews.com: Incarnate Word student, friend accused of smuggling $900,000

Redgate said his client was not close with either family member. Asked if the cash smuggling had anything to do with the pair of relatives, Redgate said, “No, it really didn’t.”

“He’s really a good kid, but got caught up in this,” Redgate said. “He’s a hard worker. He had his own businesses … selling oil products to different companies, like a middleman. He was doing pretty well.”

Redgate said his client attended university in Mexico, though he didn’t have the name of the school at hand or what he studied.

“He plans to go back and finish his education,” Redgate said.

Hoyos is originally from Mexico but has lived in Texas since at least 2013 and was attending UIW as an international student before his arrest. According to court records, Hoyos admitted to warehousing drug cash for Leal, who initially was said by agents to have admitted smuggling $1 million a week for nine months before he was caught.

Redgate, however, said that the cash loads were not that frequent or that large.

“There were a couple of trips, some (loads were) probably less than $300,000,” Redgate said. “The last one was his last one.”

Guillermo Contreras covers federal courts in San Antonio and international legal issues. Read him on our free site, mySA.com, and on our subscriber site, ExpressNews.com. | gcontreras@express-news.net | Twitter: @gmaninfedland