CARACAS, Venezuela (AP) — The last time anyone heard from Edni López was Sunday. The 33-year-old political science professor and award-winning poet was preparing to board a flight to Argentina to visit a friend when she texted from the airport that something was wrong with her passport.

“Migration took my passport because it’s showing up as expired,” she wrote her boyfriend in the message shared with The Associated Press. “I pray to God I don’t get screwed because of a system error.”

What happened next remains a mystery — one contributing to the climate of fear and repression that has engulfed Venezuela following its disputed presidential election, the most serious wave of human rights abuses since Latin America’s military dictatorships in the 1970s.

When López’s mother, Ninoska Barrios, and her friends learned she didn’t board the flight, they started frantically combing detention centers. Finally, on Tuesday — more than 48 hours later — they learned she was being held, incommunicado, by Venezuela’s feared military intelligence police on unknown criminal charges, unable to see an attorney or speak with her family.

“Please, give back my daughter,” a sobbing Barrios pleaded Tuesday outside Venezuela’s top human rights office in a video that went viral on social media. “It’s not right that a Venezuelan mother has to go through all this.”