One of the monkeys that escaped last week after a truck overturned on a Mississippi roadway was shot and killed early Sunday by a woman who says she feared for the safety of her children.

Jessica Bond Ferguson said she was alerted early Sunday by her 16-year-old son who said he thought he had seen a monkey running in the yard outside their home near Heidelberg, Mississippi. She got out bed, grabbed her firearm and her cellphone and stepped outside where she saw the monkey about 60 feet away.

Bond Ferguson said she and other residents had been warned about diseases that the escaped monkeys carried so she fired her gun.

“I did what any other mother would do to protect her children,” Bond Ferguson, who has five children ranging in age from 4 to 16, told The Associated Press. “I shot at it and it just stood there, and I shot again, and he backed up and that’s when he fell.”

The Jasper County Sheriff’s Office confirmed in a social media post that a homeowner had found one of the monkeys on their property Sunday morning but said the office didn’t have any details. The Mississippi Department of Wildlife, Fisheries, and Parks took possession of the monkey, the sheriff’s office said.

The Rhesus monkeys had been housed at the Tulane University National Biomedical Research Center in New Orleans, La., which routinely provides primates to scientific research organizations, according to the university. In a statement last week, Tulane said the monkeys do not belong to the university, and they were not being transported by the university.

A truck carrying the monkeys overturned Tuesday on Interstate 59 north of Heidelberg. Authorities have said most of the 21 monkeys were killed. The sheriff’s department has said animal experts from Tulane examined the trailer and had determined three monkeys had escaped.

The Mississippi Highway Patrol has said it was investigating the cause of the crash, which occurred about 100 miles from the state capital, Jackson.