Case:  24-1040598    
 
Date:  Saturday, April 13, 2024
 
Time:  10:55 a.m.
 
Location:  1200 block of Knollpark Circle
 
Deceased victim:  Sienna Rae Contreras, Hispanic female, 6/16/2006
 
Arrested:   Xavier Alexzander Buentello, Hispanic male, 18 years of age

On Saturday April 13, 2024, at approximately 10:55 a.m., Austin Police Department (APD) officers responded to a call for service at a residence in the 1200 block of Knollpark Circle. The caller stated that his daughter, later identified as Sienna Rae Contreras, was deceased. Officers arrived and spoke with the father who stated that he had last seen Sienna the night prior. The next morning, when he went to wake her up, he found her deceased in bed. Sienna was pronounced deceased at 11:38 a.m.
 
Homicide Detectives, Narcotics Support Unit Detectives, and Crime Scene Specialists responded to process the scene and interview witnesses. The investigation showed that Xavier Alexzander Buentello had sold fentanyl to Sienna Contreras, which caused her death hours later.  This falls under Texas Penal Code 19.02 First-Degree Murder.
 
Buentello had been in the Travis County Jail since April 29, 2024 for different charges. He has now been charged with the First-Degree Murder.
 
Anyone with any information is asked to contact the Austin Police Department at 512-974-TIPS. You may submit your tip anonymously through the Capital Area Crime Stoppers Program by visiting austincrimestoppers.org or by calling 512-472-8477.
 
This case is being investigated as Austin's 38th homicide of 2024.