University of Oregon alum Alec Zimmerman went missing earlier this week in the city of Buenos Aires, Argentina, according to The Oregonian. She was last seen in the early morning on Tues., April 9, headed to meet a truck driver for transport from Buenos Aires to Peru.

Sunni Campbell, a friend of hers, told The Oregonian that Zimmerman had been checking in regularly with friends and family throughout her journey, leading them to suspect something was wrong when they hadn’t been contacted by her for an unusually long time.

Argentinian authorities claim record of Zimmerman entering the country on March 3 but have no record of her movement up to Fri., April 12. Four days have passed since anyone has seen or heard from her.

Upon graduating from the UO, she spent over a year living in Ecuador and established herself as a vigilant, adept traveler, according to Campbell. In an email to her mother, she claimed that Angel, the truck driver with whom she was scheduled to travel to Peru, had seemed to be a “grandfatherly” type.

Zimmerman’s father will fly to Argentina on Monday to participate in the missing person’s search. Anyone with information about her whereabouts is asked to contact Argentinian authorities or the FBI.