COGAN STATION, Pa. — The discovery of the bodies of two girls missing for years and buried in the backyard of a Pennsylvania home has led to the arrest of two women.

Authorities identified the bodies of 6-year-old Nicole Snyder and 4-year-old Jasmine Snyder on Monday. Authorities say the older girl was buried in 2016, and the younger one was buried in 2017.

The girls’ mother, 32-year-old Marie Snyder, and her partner Echo Butler, 26, have been charged with child endangerment and obstruction in Lycoming County, and authorities have opened a homicide investigation, the Williamsport Sun-Gazette reported.

The girls’ bodies were transported Monday to Erie for examination by a forensic anthropologist, officials said. Chief Chris Kriner of the Old Lycoming Township police department said an investigation continues “into the manner of death, motive and the timeline of events.”

The Children and Youth Services department earlier took custody of a son for care. In early September, the agency began investigating after reports of concerns about “educational issues” involving the 7-year-old son, Kriner said. Officials then learned that Marie Snyder had two other children who were unaccounted for and last month sought help from police, he said.

Authorities said the father of the girls reported last having seen them in 2015, the same year as their last contact with medical, court or other personnel. Robert Mausteller of the township police department said officials were allegedly told in September the girls were staying with a friend, but they never got a name.

Marie Snyder was arrested at her Clinton County workplace Nov. 4 and refused to provide information about the whereabouts of the missing girls, Kriner said. The property was searched several times over the next few days, and the remains were found over the weekend.

Kriner said he and the county district attorney consider it “a terrible, horrific situation” and vowed that their investigation will not conclude until “justice is brought on behalf of these two young girls.” He said other agencies including state police and the FBI assisted in the search.

Both women were ordered held without bail pending a Nov. 17 preliminary hearing. Court documents don’t list attorneys representing the defendants; messages were left at phone numbers listed in their names.