A Tennessee Highway Patrol investigation of the school bus wreck that injured at least 27 David Crockett High School students is under way, with one focus expected to be on the bus involved in the accident.

There were still 10 students in Johnson City Medical Center as of 1 p.m. Friday. All were listed in stable condition, hospital spokeswoman Teresa Hicks said.

Bus driver Brenda K. Gray suffered minor injuries in the crash, Hicks said.

The accident happened just after 3 p.m. Thursday in the 400 block of Mt. Wesley Road, on a hilly roadway in the Mt. Wesley community.

Investigators conducted a commercial vehicle post-crash inspection Friday, and a school bus inspector examined the vehicle, THP spokeswoman Dalya Qualls said.

"Additionally, the THP's Critical Incident Response Team was also on scene to investigate the incident. The school bus was released back to the Washington County School System [Friday] afternoon," Qualls said.

Results of the bus inspection, held at the county bus garage, were not immediately available.

Several students on the bus said one or more of the bus tires appeared to be bald.

Other students and a witness to the crash commented that the bus was traveling fast on the narrow, rural road when the accident occurred.

Investigating troopers will continue their investigation "and complete a final report within the coming weeks," Qualls said.

There were 63 students on board Bus 88, which was a replacement bus, school district officials said. Driver Gray was on her regular route.

The school bus rolled at least three times before coming to rest on its side, down an embankment in a yard at 477 Mt. Wesley Road.

Numerous students were airlifted to Johnson City Medical Center.

Others were taken by ambulance to Franklin Woods Community Hospital in Johnson City, and one was treated at Holston Valley Medical Center in Kingsport.

The wreck happened "when the tires dropped off the right side of the roadway, the driver overcorrected and the bus overturned," Qualls said.

Hicks said students suffered a range of injuries. They included neck and spinal injuries, one "pretty serious" scalp laceration, broken bones and abdominal injuries.

David Crockett High School held classes as usual on Friday. Counseling was available for students.

The home football game Friday night against visiting South Greene High School went on as scheduled.

Among those first on the scene were Washington County sheriff's deputies.

Events such as the bus crash with multiple casualties pose particular challenges to deputies and other First Responders, sheriff's Capt. Shawn Judy said Friday.

"The problems that we encounter [include] setting up a triage area," Judy said. "We have to set up a command post where people can respond and find out about their loved one."

In the case of Thursday's bus crash, a command post was set up at Mt. Wesley United Methodist Church, about a half-mile from where the bus went off the road.

"You've got to keep the scene clear. There were a lot of very emotional parents, and you've got to find out where [the students] were transported," Judy said.

It is EMS protocol to not reveal who is being transported to a hospital until the ambulance arrives "at a safe location," and that delay created tense minutes of uncertainty for some parents on Thursday, Judy said.

Deputies were posted at the hospital, along with state troopers, to relay information back to the command center, Judy said.

The response from Washington County deputies, along with other First Responders, was swift and heartfelt, Judy said.

"A lot of other officers had strong feelings for the kids," he said.

Other platoons, or shifts, "called in and wanted to respond," Judy said. Many deputies did so.

Investigation protocol requires a driver to submit to a blood test following a school bus crash.

The school district is looking at any safety issues that may have been a factor in the accident, district spokeswoman Susan Kiernan said.