Police say an 18-year-old woman lost control of her car and hit a brother and sister watching fireworks in Menomonee Falls. One of the siblings, a 24-year-old man from North Carolina, died at the hospital. A 25-year-old woman, also from North Carolina, is still being treated for life-threatening injuries, that's according to police.The brother and sister have since been identified as Ben Reimers and Emily Grace Reimers, both staff members at Falls Baptist Church in Menomonee Falls. It happened Sunday night around 10 p.m. in the Pick 'n Save parking lot on Appleton Avenue near Woosencraft Drive.Police added that the driver is an 18-year-old female from Germantown, who was with two other juvenile passengers. There were no injuries to the vehicle occupants. The driver of the striking car remained on scene and was cooperative with the investigation, according to police. Initial investigation found this to be an unintentional act. Alcohol and drugs do not appear to be a factor. This crash is still under investigation by the Menomonee Falls Police Department and the Wisconsin State Patrol. Police are asking for any members of the public that witnessed this crash or have video of the crash to contact Menomonee Falls Police at 262-532-8700.