Shots were fired Saturday night outside the unoccupied home of Vice President Joe Biden in Delaware. Biden was not at home when the incident occurred, the Secret Service told reporters.

Speaking to CNN, Secret Service spokesman Robert Hoback said “a vehicle drove by the vice president’s residence at a high rate of speed and fired multiple gun shots. This occurred on a public road outside the established security perimeter. The shots were heard by Secret Service personnel posted at the residence and a vehicle was observed by an agent leaving the scene at a high rate of speed.”

Biden and his wife Jill had been planning to spend the weekend at the Delaware house. Police are investigating if anyone familiar with the Bidens’ schedules may have been involved in planning the shooting. Police are conducting a search outside the residence for evidence that could lead to the perpetrators.

“While the incident scene was being searched at approximately [9 p.m.], an individual in a vehicle attempted to pass a New Castle County police officer who was securing the outer perimeter of the area. As a result of the interaction with the officer, this individual was arrested for resisting arrest,” Hoback said. However, he added, the detainee is not suspected of being involved in the incident.