Thousands of American Express points and a Florida doctor's two Latin American "friends" were the focus of the proceedings in Sen. Robert Menendez's (D., N.J.) corruption trial Monday.

The allegations in question were tied to the prosecution's broader claim that the Democratic senator took kickbacks—expensive hotel stays, private jet flights and hundreds of thousands of dollars in campaign contributions—from Dr. Salomon Melgen in order to live a lifestyle beyond the means of a U.S. Senator, Politico reported.

The two men face charges of bribery, honest services fraud, and conspiracy, among others. Melgen offered the senator payouts in exchange for official favors, according to prosecutors. The two deny all charges.

In a 2010 email, Menendez promised to reimburse Salomon for 650,000 AmEx points he used to buy the senator a three-night stay at a Paris hotel. Specifically, Menendez planned to pay Salomon back in AmEx points himself, once he accrued them.

It would have taken the New Jersey senator 30 years to acquire that many points based on the rate he was accumulating them, American Express' VP for Membership Rewards Andrew Thomas testified. Menendez did redeem AmEx points — some 135,000 of them — to purchase a high-end grill in 2013. In 2010, when Melgen used his points to pay for the hotel, Menendez had just 58,000 points on his card. He first activated the card three years prior, in 2007.

Menendez's attorney noted Melgen's son-in-law told the senator at the time that the Paris room was the only room type available through points redemption, and the number of points spent was not revealed to the senator.

The prosecution also called former Menendez policy adviser Mark Lopes, who testified how his former boss helped to bring Melgen's girlfriends into the country.

The prosecution showed emails between Menendez, Lopes, and state department officials that supported the visa applications for Brazilian law student and former actress Juliana Lopes-Leite, as well as for a Dominican woman and her sister. The women were referred to as "friends" of Melgen's in the emails. The official indictment refers to the women as Melgen's girlfriends.

One email, subject line, "Dr. Melgen request," including Lopes telling the senator "we are preparing a general letter of support from you," and asking, "ok to send, right?"

"Yes, as well as call if necessary," Menendez replied.

The trial is projected to last around six weeks.