An exhilarating professional basketball championship for the city of San Antonio was tragically marred by the news over the weekend of the catastrophic head injury of a young fan who fell from a moving vehicle while celebrating his team’s victory earlier in the week.

The San Antonio Spurs beat the Oklahoma City Thunder on Thursday and then went on to close out the seven-game series on Saturday with another win that gave the team the Western Conference championship.

However, one of the team’s excited fans, identified as 17-year-old Jose “Joey” Rodriguez, is in critical condition and was reported by relatives and San Antonio police to be brain dead following Thursday’s freak accident, and he is not expected to survive, the San Antonio Express-News reported.

The teen was sitting on the passenger-side window of a vehicle when it hit a curb, causing him to fall and hit his head on the pavement, his aunt, Yvonne Hudson, told the newspaper.

“He left blood all over the street,” she said.

Rodriguez was taken to an emergency room but transported to another local hospital due to the severity of his injuries.

Expected to graduate from the Frank Tejeda Academy next year, Rodriguez also works at a restaurant called Bill Miller Bar-B-Q and has a “kind heart” and a “willingness to help others,” according to family members.

Ironically, the accident came after the family was concerned about the boy’s safety during the celebration.

According to the newspaper:

The incident happened in the 300 block of West Dickson Avenue, just north of Southwest Military Drive, according to the preliminary police report. San Antonio police had diverted traffic from Southwest Military Drive to side streets to help keep vehicles moving through the crowded celebration area.

Hudson said that when her nephew initially asked his parents for permission to celebrate the Spurs’ win, they said no because of the “nonsense” happening there. But Rodriguez told them that a parent would go with them, and they agreed. Rodriguez instead went only with friends, Hudson said.

The exact circumstances behind Thursday’s incident remain under investigation, the New York Post reported.

“The San Antonio Police Department extends our sympathy to the family, friends and loved ones affected by this tragic and preventable incident,” the department said in a statement.

“This serves as an important reminder that public safety is a shared responsibility. We encourage everyone celebrating to follow traffic laws, stay inside of your vehicles and follow directions from the officers who are there to keep everyone safe,” the statement concluded.

The Spurs will face the New York Knicks in the NBA Finals. At the beginning of the season, the Spurs were massive underdogs to win the NBA championship and remain underdogs in their coming series against the Knicks.

It has not been determined what will happen to the teenager in the coming days. His aunt told a reporter doctors want to disconnect Rodriguez from life support.

Contributor Lowell Cauffiel is the author of the New York Times true crime best seller House of Secrets and nine other crime novels and nonfiction titles. See lowellcauffiel.com for more.