Investigators in Medellín, Colombia, say they have made significant progress in locating a missing American Airlines flight attendant who disappeared during a crew layover in the South American country over the weekend.

In a press conference on Thursday, Manuel Villa Mejía, secretary of security of Medellín, said investigators have identified the people last seen with 32-year-old Eric Fernando Gutierrez Molina, a U.S. citizen and flight attendant based in Dallas-Fort Worth, who was last seen Saturday night.

Officials said Gutierrez Molina went out with two coworkers, a man and a woman, and later left with the woman and other unknown people for another establishment.

Officials said on Thursday that they have now identified those other people and that they have a history of committing theft using scopolamine, an incapacitating drug known as “devil’s breath” with a history of being used in assaults in the country.

Investigators in Colombia have not released the names of the people who are believed to have been with Gutierrez Molina or said whether they have been taken into custody and questioned, but they have identified vehicles and phones used by the suspects.

Friends of Gutierrez Molina are speaking out now, days since his disappearance. His boyfriend, Ernesto Carranza, said he knew something was wrong Sunday morning.

“That’s when I said this is odd. I knew immediately, because even though he has his own phone, his work phone could’ve been a second option of communication,” said Carranza.

Carranza said Gutierrez Molina last made contact Saturday night, before messages stopped going through.

“I messaged him have a good night, be safe, I love you. And he just messaged back, ‘ok I love you back I’m going to go out and hang with my crews,’” he said.

Gutierrez Molina’s disappearance has taken a toll.

“It’s the worst feeling ever, not knowing. The uncertainty. Keeping faith, but at the same time we’re all human,” said Carranza.

Longtime friend Sharom Gil told NBC 5 she’s also desperate for answers.

“We’re sending information to who we need to,” Gil said. “We’ve contacted the police here in the area. We’ve also contacted the [U.S.] Embassy. We’ve posted all over social media, and we’ve been getting people who want to help.”

As of this writing, Gutierrez Molina’s location remains unknown.

What is scopolamine?

According to the U.S. Embassy in Colombia, scopolamine has been used for years to carry out robberies of people targeted while visiting bars and nightclubs in Medellín, Cartagena, and Bogotá.

The drug is a sedative that often leaves the victim disoriented, with no memory and sedated, “so they are easily robbed.”

The embassy said that if the drug is ingested or exposed, it can leave a victim unconscious for 24 hours or more and that overdoses can cause respiratory failure and death.

Dr. Jairo Noreña said scopolamine is an extract that comes from a plant found in the country and that the plant’s seeds can be crushed into an odorless, tasteless powder that can be mixed into drinks. Authorities in Colombia said the drug is common enough that some bars and clubs warn customers with signs that urge them to stay alert and report anything suspicious.

Carlos Zapata, Telemundo 39

Carlos Zapata, Telemundo 39

Investigation opened into a missing American Airlines employee

According to local reports from Telemedellín, Gutierrez Molina arrived in Colombia on Saturday night on a flight from Miami and was due to fly back to Miami the next morning.

Sharom Gil, a close friend of Molina’s who spoke to Telemedellín, said Molina and another colleague decided to leave the hotel to go out on the town. Gil said Molina and the coworker met two guys at a club and decided to “take the party to another place” when the club closed.

Molina never made it back to the hotel and the events surrounding his disappearance remain unclear.

Local authorities in Medellin issued a missing-persons alert saying Molina was last seen early Sunday in the La America neighborhood, a mostly residential area.

Gil said they filed missing persons reports in both Addison, Texas, and Medellín and that the airline notified the U.S. Embassy in Colombia of his disappearance. Addison Police said the FBI’s Dallas Field Office is managing the case.

In a statement to NBC 5, American Airlines said: “We are actively engaged with local law enforcement officials in their investigation and doing all we can to support our team member’s family during this time.”

The Association of Professional Flight Attendants, the union representing American Airlines flight attendants, told NBC 5 it was “actively supporting all efforts to help locate our missing colleague in Colombia.”

Arturo Fontes is a retired FBI agent with nearly 30 years of experience. Fontes later founded his own company and spent extensive time in South America working on missing-person cases, which he said often end with the person found dazed but alive.

“These cases are normal. In this case, he has not shown up and that’s what’s giving some red flags,” said Fontes.

Fontes said the sense of urgency among officials in Colombia is critical.

“What they’re going to do normally is go to the last location he’s been to, whether it’s a bar or a restaurant,” he said. “And then they’re going to track maybe the cameras and try to locate where the last place he went. If he had a cellphone, the first thing they will look at is the telephone to see what his last location was.”