The brain of the Plano teen who stabbed his mother and brother to death before killing himself has been donated to the scientific community for concussion research.
Police say 19-year-old McCann Utu, Jr. killed his mother, Stacy Fawcett, and his 17-year-old brother, Josiah Utu, last Friday before killing himself.
McCann's uncle, Scott Fawcett, says the 19-year-old's personality changed after he suffered two head injuries while playing basketball at Plano West High School.
"As I've told many people over the last few days, if you showed me two pictures of him that were four days apart centered around the second concussion, I could tell you by the look on his face which one was the later one," said Scott.
Dr. Nimesh Patel, a neurosurgeon at Methodist Brain and Spine says brain damage can impact your ability to control your emotions.
"The brain is in balance with emotions," said Patel. "There is factual evidence that if you have repetitive brain injury, it can cause changing patterns of thinking and behavior. That's well documented."
"A hit to the body can sling the head back and forth as well," explained Patel. "It's not just football. It's soccer. It could be tennis or race car drivers. A lot of things sling the head back and forth that could cause repetitive damage to the brain."
Patel says only recently have scientists learned that repetitive brain damage leads to chronic traumatic encephalopathy. He says they have only hit the 'tip of the iceberg.'
Scott hopes his nephew's brain will be able to help scientists learn more about the impact of concussions on the brain and how they may lead to violent irrational behavior.
"A year ago, we started a relationship with a psychologist here in Plano. A year ago, we started doing everything we could to help him," said Scott. "We did see it coming, but what do you do? Do you call the police and say, 'Hey, this 19-year-old is acting a little different?'"
Scott explained McCann had never been violent before Friday, or they would have called police.
A public memorial was held Tuesday for the family at Prestonwood Baptist Church. Thousands gathered to pay their respects to a mother many knew from TV culinary segments and her teenage sons. Family members say the two brothers were only 14 months apart and were best friends.