Two American cyclists were among four people killed Sunday by a hit-and-run driver in Tajikistan, in what authorities believe could have been a deliberate terror attack. The tourists—from the U.S., Switzerland, and the Netherlands—were killed and three more were injured. One is also reported to have suffered from a stab wound. “We are looking into all versions— accident, robbery... including a terrorist act,” said the Central Asian country’s interior minister, Ramazon Rakhimzoda. Investigators identified a damaged vehicle that showed “involvement in the commission of this crime” in a nearby village, according to a statement sent to CNN from the Tajikistan interior ministry. One suspect was arrested while another was killed. Three more suspects remain at large, including the owner of the car that police believe struck the tourists. According to SITE Intelligence Group, the Islamic State has claimed credit for the attack.