Three monkeys were still on the loose Wednesday in Mississippi after a truck carrying the research animals overturned, but it remained unclear who owns the monkeys, who was transporting them and where they were being taken.

The monkey mystery left a host of unanswered questions for authorities.

Officials said at midday Tuesday that all but one of the escaped Rhesus monkeys had been killed. But the Jasper County Sheriff’s Department later said officials from Tulane University got into the trailer Tuesday evening and determined three monkeys had escaped.

Sheriff Randy Johnson said Tulane officials reported the monkeys were not infectious, despite initial reports from the truck’s occupants warning that the monkeys were dangerous and harboring various diseases. But Johnson said in a statement that the monkeys still needed to be “neutralized” because of their aggressive nature.

The monkeys were being housed at the Tulane University National Biomedical Research Center, which routinely provides primates to scientific research organizations, according to the New Orleans school. The research center is about 40 miles (65 kilometers) north of New Orleans in Covington, Louisiana.

AP Video / Sophie Bates