The bodies of two nuns who had been stabbed to death were found on Thursday at their home in Duant, Mississippi, police have confirmed.
Officials told local media they are investigating the case as a robbery that escalated into murder.
Sister Paula Merrill, of the Sisters of Charity of Nazareth (SCN) in Kentucky, and Sister Margaret Held of the School Sisters of St. Francis in Milwaukee, both 68, were nurse practitioners and worked at the Lexington Medical Clinic.
They helped provide medical care for families and individuals who couldn't otherwise afford it.
Merrill and Held had not arrived at work, about 60 miles northeast of Jackson, on Thursday morning. Their bodies were found by a co-worker, police told local media.
No arrests have been made yet, but a spokesman for the Mississippi Department of Public Safety said a blue Toyota Corolla missing from the home of the two nuns was found abandoned on a secluded street about a mile away on Thursday evening.
The car has been taken to a state crime lab for analysis.
Rev Greg Plata, who leads the church attended by the two nuns, said they were "two of the sweetest, most gentle women you can imagine. Their vocation was helping the poor."
"People were attracted to them because of their goodness," he told the New York Times.
Bishop of Jackson, Joseph Kopacz, said: "These sisters have spent years of dedicated service here in Mississippi. They absolutely loved the people in their community."
"Pray in gratitude for the precious lives of Sisters Paula and Margaret... They served the poor so well. Because we are gospel women, please also pray for the perpetrators," SCN President Susan Gatz said in a statement.
The Mississippi secretary of state, Delbert Hosemann, said he hoped justice would be "swiftly served".
"Unbridled love and care for mankind has been met with unparalleled savagery," he added in a statement.
Additional reporting by Reuters
