The wreck happened late Saturday night on Queenslake and Cypress Rosehill in northwest Harris County.
At about 10:30 p.m., a Harris County Precinct 4 deputy saw a car driving toward him at a high rate of speed, according to authorities. He turned around and gave chase, but when the car the girls were in flipped over at Queenslake Drive, the deputy allegedly turned off his lights and sirens -- and drove off.
In a news conference, Sheriff Ed Gonzalez alleged the deputy saw the accident but did not stop.
"From everything we've heard today, it seems the deputy constable was aware of what had occurred," Gonzalez said.
The deputy didn't say anything about the chase until a supervisor found in-car footage of the chase and questioned him about the circumstances regarding the crash, according to a news release.
Precinct 4 brought the dash cam video to the attention of the Harris County Sheriff's Office and asked the HCSO to investigate. No charges have been filed. The case is under investigation by the Harris County District Attorney's Office.
However, the sheriff's comments contradicted what Constable Mark Herman told Eyewitness News on Wednesday afternoon. Herman said the deputy claimed to have seen the car speeding and started chasing it. He said the deputy then lost the car and didn't realize the car had crashed. Constable Herman said the deputy then proceeded to look for the car but never found it. When discussing the deputy, Herman said that he didn't leave the scene, because there was no scene to leave.
Harris County Precinct 4 Constable's Office says the deputy has been fired, and the victims' families have been notified. Herman said the deputy was fired because he failed to follow policy during the chase. He said his firing was not related to the crash.
Gonzalez extended his condolences to the girls' families and pledged to oversee a "complete and thorough investigation."
The girls were Cypress Falls High School students. The driver, Jenna Ellsmore, was airlifted to the hospital in critical condition. The passenger, 16-year-old Lily Haugen, died at the scene.
"I love her so much. I want her to know how much she means to me," said Haugen's best friend, Danielle Taylor.
KTRK-TV also talked to Ellsmore's mother who said she was upset that the deputy did not stop.
"That was very heartbreaking," said Kathy Ellsmore-Gleason, Jenna Ellsmore's mother.