Family and friends are asking for the public's help in locating University of Texas doctorate student Frank Guzman, who along with his wife, Caroline Katba, has been missing since late July, according to the Texas Missing Persons Clearinghouse Bulletin.

Guzman and Katba were traveling in Mexico when their families lost contact with them around July 22, according to a social media post from Guzman's sibling, Liz Guzman.

In an interview with the Austin American-Statesman, part of the USA TODAY Network, Guzman said their brother and sister-in-law were traveling by car through Latin America to Chile, where Frank was expected to do fieldwork and research for his doctorate degree at UT.

Guzman said the couple would frequently text their families with pictures and updates, but on July 22 they both went "offline" on WhatsApp. They last heard from her brother earlier that day.

"He told me he was arriving at his next hotel around 3 p.m., we're an hour ahead, maybe I give you a call around 3 or 4 your time," Guzman said. They never got a call.

Both families have attempted to reach the pair multiple times throughout the summer, Guzman said, but thought the couple may have lost service or connection as they traveled south. Nonetheless their worry grew throughout the summer and when a UT professor contacted Guzman's dad to tell him Frank had not shown up to class, Guzman said.

"My brother has completed 12 years of effort into this degree, he wouldn't just leave it," Guzman said.

Guzman said a security team hired by the University of Texas believes the pair were last spotted in Coatzacoalcos, a city in Veracruz, Mexico. She added that the team told the family that there is no documentation of them leaving Mexico, as they had planned to do July 22.

Guzman has filed missing person reports for their brother in Mexico and Texas, and there is also a missing person's report in Mexico for Katba. Guzman has also contacted the U.S. Embassy and FBI, they said.

Frank Guzman is an anthropology student at UT's College of Liberal Arts. According to his LinkedIn page, he has been a Longhorn since 2020, and studied previously at Penn State University and Stanford University. Katba is in the process of opening a business, Guzman said.

UT spokesperson Mike Rosen said the university can't speak to specific cases or confirm or deny if someone is missing due to the Family Education Rights and Privacy Act, but he said that in emergencies abroad involving individuals doing UT work or on UT programs, the university deploys its international Critical Incident Response Team, which collaborates with the U.S. State Department, embassies and international authorities to best help.

"In the case of a missing student, UT would provide assistance and resources to the fullest possible extent to help ensure every effort is made to locate and assist the student," Rosen said.

Guzman is asking people with connections to the area to spread word of the missing couple, and for anyone with information to promptly contact the family.

"They were just traveling, and they would have never disappeared out of nowhere. They had an end goal," Guzman said. "He's just a student, he's just a regular guy."