The remains of 2,411 fetuses found in Illinois last year after the death of a former abortion provider have been buried, but authorities say they're no closer to knowing why the doctor had been keeping them.

The remains were buried together in a donated plot on Wednesday afternoon following a graveside service in South Bend, Ind. They were found last year after the death of Dr. Ulrich Klopfer, who had worked as an abortion provider at three clinics in Indiana.

Klopfer was living in Illinois when he died in September at age 79. Soon afterward, officials discovered the remains in his home and vehicle. Officials say they date back to the years from 2000 to 2003.

Indiana's Republican attorney general, Curtis Hill, who has been leading an investigation into the matter, presided over the memorial service.

"While it would have been preferable to return the remains to each city where the procedure took place, that was not possible, due to the degradation of the remains and the unreliability of the records," Hill told onlookers.

Hill noted that an Indiana law passed in 2016 — long after the procedures in question — requires the burial or cremation of fetal remains resulting from an abortion. The law was signed by then-Gov. Mike Pence and upheld by the U.S. Supreme Court last year.

In an interview with NPR, Hill said his office has been combing through "thousands" of records found at Klopfer's home outside Chicago and at three clinics in Indiana. But Hill said that Klopfer's motivation for keeping the remains is still unclear and may never be known.

The remains themselves — which had been sealed in plastic bags and stored in boxes — had "degraded," and the medical records were in "deplorable" condition, complicating the investigative process, Hill said.

"Lots of the records were spoiled, or destroyed, or wet," he said.

Hill declined to comment on whether he is speaking with former clinic staff members, citing an ongoing investigation.

He said his office has heard from about 180 people through an information hotline for former patients, many of whom were not patients at the time of the procedures.

Hill said he believes Klopfer transported the remains from the clinics in Indiana to his home in Illinois. He said his office is still examining records, but he expressed little hope of finding an explanation for Klopfer's actions.

"In terms of the why ... we may never know," Hill said. "The best evidence of the why certainly died with Dr. Klopfer in September. ... There's no answer for that, and I don't know that we ever will get an answer for that."

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