The children were hit while boarding a bus near 4600 N State Road 25 in Rochester in Fulton County at about 7:15 a.m., police said. Rochester is located about 45 miles south of South Bend.
Police said the children were two 6-year-old twin boys and their 9-year-old sister. They have been identified 6-year-old Xzavier and Mason Ingle and 9-year-old Alivia Stahl. All three were students at Mentone Elementary School.
An 11-year-old boy who suffered several broken bones was airlifted to a hospital in Fort Wayne, Indiana.
The 24-year-old driver of a 2017 Toyota Tacoma stayed at the scene and she is cooperating with authorities. Police said it is unclear why she did not stop and the bus had deployed its arm with a stop sign.
""I haven't seen first responders and troopers cry in a long time," Indiana State Police Sergeant Tony Slocum said. "When the children's father had to make identification of his children, that was just gut-wrenching. We saw tears today and our hearts just go out to them because most of us have children and we can't imagine the pain that he felt today. It was heartbreaking It's still heartbreaking."
Police said the driver is from rural Rochester. Indiana State Police are investigating.
"We all have a responsibility to make sure our children get to and from school safely," Slocum said. "When we're traveling in the early morning hours and early evening hours we've got to anticipate school buses are going to be out. When those stop arms are extended, by law, you are required to stop. This is the exact reason why. We don't want another family to have to go through this."
The school corporation said in a statement, "Our school corporation has suffered a tragedy this morning. We have learned of three student fatalities and one student seriously injured and airlifted to a Fort Wayne hospital as they were hit by a vehicle while boarding their bus.
We have deployed all school counselors to meet the emotional needs of our staff, students and parents.
We are awaiting to learn more confirmed details but wish to ask the community to come together to pray for the families, our students and our staff."