Steven and Jean Lopez, brothers in what is often called the “First Family of Taekwondo,” were allowed to participate in last summer’s Rio Games even though they were being investigated for sexual misconduct, and the allegations against them have since drawn the interest of the FBI.

USA Taekwondo began investigating the Lopezes more than two years ago after receiving complaints that they had allegedly sexually assaulted multiple women. No hearings were held and USA Taekwondo, after consulting with the U.S. Olympic Committee agreed to put the inquiries on hold before the Rio Games, meaning two-time Olympic champion Steven and longtime coach Jean were free to represent the United States.

But USA Taekwondo and the investigating attorney, Donald Alperstein, had enough concern that he shared information with the FBI and alerted police in the Lopezes’ hometown of Sugar Land, Texas.

In a March 22 letter to one of the women, which was obtained by USA TODAY Sports, Alperstein said he notified the FBI “because so much of the misconduct occurred in multiple jurisdictions.” He also said he “felt the Lopez brothers needed to be removed from the sport.”

Mandy Meloon, a former taekwondo athlete who has accused Jean Lopez of molesting her, said she was interviewed by an FBI agent for about two hours on May 19. Meloon says the agent questioned her about Jean and Steven Lopez regarding “stuff that happened on the national team when we traveled internationally.”

Meloon says she gave the agent names of women who had allegedly been abused — by the Lopezes and others in the sport — to contact.

Mary Holligan, a warden at the Lockhart (Texas) Work Facility where Meloon was released Tuesday after being sentenced to two years for assaulting a sheriff’s deputy, confirmed the agent’s visit.

Alperstein declined to discuss specific cases when contacted by USA TODAY Sports. But he acknowledged that he reported whatever information he thought was necessary to law-enforcement authorities, including the FBI. The FBI contacted him in response to that, and he was interviewed by phone last month.

The FBI would neither confirm nor deny the existence of an investigation, said Shauna Dunlap, a special agent and spokesperson for the bureau’s Houston office.

In separate interviews, Steven and Jean Lopez denied allegations of sexual assault made by four women to USA TODAY Sports and investigators.

“I’ve never been inappropriate with anyone,” Jean Lopez said.

Steven Lopez said he was told in January 2016 that there was a complaint against him with USA Taekwondo. But he said he was not given any details of the allegations, nor was he interviewed by Alperstein or anyone else.

Lopez says he was told in a letter last month that the complaint was being transferred to the U.S. Center for SafeSport. The independent agency, which became fully operational in March, was created by the USOC to handle abuse allegations for national governing bodies.

“I’ve never — nothing, nothing at all,” Steven Lopez said when asked if he’s ever sexually assaulted or committed any kind of inappropriate behavior with any woman. “Nothing like that. Nothing close to that.”

Steven Lopez, 38, is taekwondo’s biggest star and the most decorated athlete in that sport. He is a five-time Olympian with gold medals in 2000 and 2004 and a bronze in 2008, as well as five world titles. He was featured in Coca-Cola’s “six pack” before the Beijing Games in 2008, a promotional campaign that also included LeBron James and Shawn Johnson.

His younger siblings, Diana and Mark, also won medals in Beijing. All three were coached by the eldest Lopez sibling, Jean, 43, who also coached at the 2004, ’12 and ’16 Olympics.

In addition to notifying the FBI, Alperstein said he told Sugar Land authorities that the brothers “may have committed sex crimes involving minors,” according to a Nov. 22 email obtained by USA TODAY Sports. The Fort Bend County (Texas) sheriff would have jurisdiction.

A request by USA TODAY Sports for records pertaining to the Lopezes or Alperstein’s alert was rejected by Fort Bend County attorney Roy L. Cordes Jr., who said they were not subject to public disclosure.

The USOC has been criticized for not taking a more proactive role in addressing sexual abuse allegations within the national governing bodies that oversee each sport, with scandals over the past decade involving USA Gymnastics, USA Swimming and US Speedskating.

USA Taekwondo consulted with the USOC on the Lopez investigations before the decision was made to allow them to go to Rio, according to a former federation official who was told by the organization’s executive director, Keith Ferguson. The official spoke to USA TODAY Sports on condition of anonymity because of the sensitive nature of the allegations.

USA Taekwondo told USA TODAY Sports it does not discuss ongoing investigations. But in a statement, the federation said it “places tremendous importance on protecting and preserving the safety of our athletes.”

“USA Taekwondo gave Mr. Alperstein a broad charge and unfettered ability to carry out his task -- to expeditiously chase down every complaint, talk to every witness, gather hard actionable evidence and prosecute fully any violations, no matter where the evidence led,” USA Taekwondo said.

“Additionally, as he uncovered evidence USA Taekwondo has diligently provided any and all information to relevant law enforcement agencies, including local police and the FBI.”

USA Taekwondo turned over all the investigations and its work to the U.S. Center for SafeSport in March, according to spokesman Steve McNally

USA TODAY Sports spoke with eight people who were interviewed as part of USA Taekwondo’s investigations of Steven and Jean Lopez, including the four women who said they were sexually assaulted by the brothers.

Heidi Gilbert and Meloon, two of the women, spoke on the record. The other people, including the two other alleged victims, requested anonymity because they said they fear retribution by USA Taekwondo or the Lopezes.

Steven Lopez is scheduled to compete at the world championships later this month in Muju, South Korea. Jean Lopez was not selected as a coach for the team but said he will attend the championships.