Anusha Chaganti, 14, and her brother Vivek Chaganti, 9, were both killed with their physician father.
About 10:40 p.m. Monday, a semi tanker carrying nitric acid rolled over while heading south on I-65 near Route 10 in Jasper County, according to Indiana State Police. No one was injured in the rollover.
About an hour later, a semi was slowed in the northbound lane of I-65 for the rollover crash when a 2008 Toyota Sequoia failed to slow down and rear-ended the semi-trailer, police said.
The driver of the Sequoia, 45-year-old Dr. Mallik Chaganti of Rensselaer, Ind., along with his son and daughter, were killed in the crash, police said.
A third child, a boy, was injured and airlifted to Loyola in Maywood. All of the children at one time attended St. Augustine Catholic School in Rensselaer. One child was still at school. The family's medical practice was closed Tuesday, and is directly across from Jasper County Hospital where the doctor had privileges.
The driver of the semi, a 31-year-old Washington state man, was not injured, police said.
Neither drugs nor alcohol are thought to be contributing factors in the crash, police said, though the investigation is ongoing.
Southbound I-65 between Routes 2 and 14 was reopened about 10 a.m., and one lane and the shoulder of the northbound lanes were open as of noon, though crews are still at the scene cleaning up the nitric acid.
The Sun-Times Media Wire contributed to this report.