Southwest High School in Minneapolis went into a temporary lockdown after students reported hearing gunshots nearby.
The incident happened at 11:21 a.m. on Wednesday, with the shots reported in the area of Pershing Park, Minneapolis police told Bring Me The News.
It emerged that some students near the park told the School Resource Officer on duty they heard what sounded like three gunshots, before seeing an SUV leaving the area "at a high rate of speed."
A second vehicle was seen traveling after the SUV, possibly in pursuit.
Officers responding to the area found no visible signs that a gun was discharged – no casings, no victims and no signs of property damage.
Further investigation determined that the SUV driver is a student at the high school, and they have not been back to school since it happened.
"Officers have checked the residence in the neighboring city where this student resides," police spokesman John Elder said.
"There is no sign of the student or the vehicle. Checks of all medical facilities show that no one has been treated for this type of injury."
The school was placed on a temporary, Code Yellow Lockdown while the reports were investigated.
A Code Yellow is put in place when there's a perceived threat outside of a school building. It requires all exterior and interior doors be locked and security at entrances be increased, though students are still allowed to pass from class to class.
The incident remains under investigation.