Devos had always considered herself as a person with moderate feelings towards the Ansata until she was assigned to work in a city with high terrorism threats. A few days later, the Ansata destroyed a shuttlebus with sixty schoolchildren with a bomb, planted by a teenager. There were no survivors. The terrorist organization claimed it was a mistake and that they intended to destroy a police transport. On that day, Devos pledged to end terrorism in the city. However, she vowed not to use the methods of her predecessors, which often resulted in people mysteriously vanishing from the police station. Devos' view of the Ansata deteriorated over the next six months, partly because of the rising body count she had to deal with, but mostly because of the three assassination attempts on her life in that time. She was further dismayed when the Ansata started using inverters to cause more destruction.
In 2366, Devos responded to another attack at the Lumar Cafe. This time, crewmembers from the USS Enterprise-D were present while medical supplies were being delivered. Dr. Beverly Crusher was kidnapped by the Ansata, and so Devos worked with Commander William T. Riker to identify the technology they used for transportation. Devos interrogated adults and children alike to find information. Riker questioned her methods, and, instead, informed one of the terrorists, Katik Shaw, that they would negotiate for Crusher's release. The Ansata responded by attempting to destroy the Enterprise and kidnapping Captain Jean-Luc Picard.
When the Enterprise determined the Ansata's hiding location, Devos assisted in the surprise attack. Devos shot the Ansata's leader, Kyril Finn, to death after he appeared ready to execute Picard. Riker rebuked her, but she stated that if Finn were taken alive, there would have been more bloodshed in any attempts to free him. A young Ansata boy afterwards aimed a phaser rifle at Devos, but she was saved when Dr. Crusher urged the boy to put the weapon down. (TNG: "The High Ground")