A Dutch team is helping the Colombian military search for four children who may be wandering lost in the Amazon rain forest. Their Cessna C206 plane crashed on May 1, and there are signs that the kids survived the crash, RTL Nieuws reports.

Lesly (13), Soleiny (9), Tien (4), and Cristin (11 months) were flying with three adults to San Jose del Guaviare in central Colombia when their small plane disappeared from the radar. The cause of the crash is still unknown.

The Colombian authorities immediately started searching. They only found the plane and the bodies of the three adults earlier this week, on May 16. About 100 Colombian soldiers with three dogs are searching for the children. A plane with a powerful loudspeaker is flying over the area, playing an audio message recorded by the children’s grandmother.

The Dutch Anne van den Ouwelant and her husband have been closely involved in the search since May 8 on behalf of the aid organization Rescue International. She works for an organization that helps traumatized children. And her husband, Humberto, is an expert in data analysis.

“By analyzing radar images and other data, Rescue International was able to make the search more specific,” Van den Ouwelant told RTL. “Partly because of this, the plane could be found.” The Colombian army also found traces that the children are alive, including a shelter, eaten fruit, and a baby’s drinking bottle.

“Now that they have the plane, it is important to look at lost persons behavior. So: what do people do in such a situation? A person needs water, so they will go to places with water. It makes a difference that they have a 13-year-old with them in terms of creativity and stamina. The disadvantage, of course, remains that it involves children.” There’s a solid chance that a 13-year-old will know to look for water or mark where they’ve been so that they don’t walk in circles, for example.

Another helpful tip Van den Ouwelant could give the searchers on the ground is that people in distress tend to take the path of least resistance. “So if there are hiker’s trails nearby or trails that animals use, people are more likely to choose that path. And now something else has been added: people often try to walk to a high point to get a signal with their phone.”

The Dutch woman doesn’t dare to guess whether these children, including a baby, could survive for over two weeks in the jungle. “But there is hope. You should always keep that. These children may still be alive. An advantage, for example, is that they are from the indigenous population, so they may be a little familiar with the terrain.”