Tezsla's other daughters, Sophie and Natalie, were in critical condition Thursday evening at Cooper University Hospital in Camden along with the other Chesterfield Elementary pupil, Jonathan Zdybel, also 11, a hospital spokeswoman said.
Fifteen other children sustained injuries such as bumps, bruises and cuts, police said, and were treated at nearby hospitals.
Tezsla's neighbors declined to comment on Thursday. There were signs of the children around the one-story home: a basketball and a volleyball on the grass, a sled leaning up against the front of the house with two ice skates hanging from it.
The State Police tweeted condolences: "NJSP hearts go out to the Tezsla family for the loss of their daughter & prayers for the recovery of the injured children."
John Kelly, whose 11-year-old daughter attends Chesterfield Elementary, said the Tezsla girls were in his house recently and played with his daughter, the Associated Press reported.
"It's devastating. My wife can't come out or anything," said Kelly, who was picking up his daughter, who walks to school.
Township Police Chief Kyle Wilson said the dump truck, belonging to Herman's Trucking of Wrightstown, was traveling along Bordentown-Chesterfield Road (County Route 528) and the bus along Old York Road when the truck struck the bus on the driver's side at the intersection at 8:05 a.m.
The impact, toward the rear of the bus, sent the vehicle into a light pole.
About 25 children were on the bus, Wilson said. He said he could not say where Isabelle was sitting.
EMS units were on the scene in less than two minutes, Wilson said, and a house at the intersection was used as a triage station.
A boy being taken from the scene told the AP that "this big truck just came and slammed right into us." The boy said some students left the crash with bloody faces. His mother did not want the boy's name used.
Wilson said he did not know how many of the children were wearing seat belts. Students on the bus said they were wearing seat belts, but the mother of one child told NBC10 that some children were tossed into the aisle.
"Our thoughts and prayers are extended to all families involved," Wilson told a news conference at the township hall.
The drivers did not appear to have serious injuries, he said.
There are a stop sign and a flashing red light on Old York Road and a flashing amber light on Route 528, suggesting that the truck had the right of way, Wilson said. He said it appeared that both lights were working. He said no charges had been filed pending an investigation.
The AP, citing police, said the bus driver was John Tieman, 66, of Beverly, and the truck driver was Michael Caporale, 38, of New Egypt, N.J.
Ellen McHenry, superintendent of Chesterfield Elementary, said the school continued operating with grief counselors on hand. She said the school, which is scheduled to be closed Friday for the Presidents' Day holiday, will have counselors available in the morning.
"Today's events are obviously tragic for young children," she said, asking news media to respect the privacy of families involved.
Parents at the school declined to speak to reporters during dismissal. One said her child did not know about the crash, and a school official asked reporters to stand out of earshot of the children.
McHenry said the school did not tell students about the nature of the accident and planned to send notes home with them.
"We're going to ask parents to talk to students about the seriousness" of the crash," she told reporters.
Wilson said Chesterfield Baptist Church planned to hold a candlelight service Thursday night.
In a statement, Gov. Christie called the accident "a terrible tragedy" and said his family sent "our thoughts and prayers" to the Tezslas and the other injured children.
Contact staff writer Darran Simon at 856-779-3829, firstname.lastname@example.org, or @darransimon on Twitter.
This article contains information from the Associated Press.