HOUSTON (KTRK) -- A family is beginning their Easter in tragedy after a 10-year-old boy was killed and his infant sister was injured in an accident in north Harris County.Investigators say sadly it didn't have to end this way.The accident happened around 8:40pm Saturday on State Highway 249 and McKinley Road.Juan Esparza was turning his Toyota Sienna minivan into the parking lot of a go-kart facility when the driver of a BMW SUV slammed into the back of their vehicle. With Esparza inside the vehicle were his wife and four children.Brian Esparza, 10, died as a result of his injuries, while his 7-month-old sister is fighting for her life.The minivan has unbelievable damage, showing how violent of a crash occurred.A man and woman in the driver and passenger seats were not hurt, nor the two teenagers in the middle row. But it was in the back seat where the little boy was severely injured. He died at the hospital from his injuries.Investigators say the victim was not wearing a seat belt when the crash occurred, and that certainly was a factor in the severity of his injuries.The 7-month-old was also not strapped into her car seat because we are told it was broken. She was sitting in someone else's lap when the two cars collided.Investigators say a seat belt would have possibly saved the life of the boy.Rijan Growe, who was driving the BMW SUV which rear-ended that minivan, was not injured. Officers say neither driver was intoxicated, and drugs and alcohol did not play a role in any of this.Deputies hope to find surveillance videos to help give them a better idea of which lanes the car and minivan were in when they crashed.Many questions remain as to why this accident happened. We'll bring you the very latest when we get it.We're following this story on Eyewitness News. Watch for updates on air, online and on our mobile news app.