BUTLER TWP — The mother of 4-year-old Bentley Thomas Miller is the latest defendant to be charged in the wake of her son's slaying.

Butler Township police Thursday arrested Mac-Kenzie Paige Peters, 21, of Butler on two felony counts of child endangerment. She was arraigned and later released on $25,000 unsecured bail.

Investigators allege Peters “failed to seek appropriate medical treatment” for a “severe burn” Bentley suffered to the top of his hand and wrist while in the care of her boyfriend, Keith Jordan Lambing.

Police said Lambing, 20, was baby-sitting the boy at the Super 8 hotel in Butler Township on March 21 when he sexually assaulted the child. The alleged assault caused Bentley to bleed to death, according to the court documents.

The child had numerous other injuries, authorities said.

Lambing is charged with homicide, rape of a child and a list of other charges in the death. He is being held in Butler County Prison without bail in the case.

Lambing and Peters had been staying at the Super 8 for four to six days when the boy died. While searching the couple's room, documents said, police found “evidence of drugs and/or drug paraphernalia.”

Also at the motel with the couple was Peters' 4-month-old son, police said.

Investigators described Bentley's burn as “being significant enough that any reasonable caretaker would have sought medical treatment for wound care and pain management,” documents said.

Lambing called his mother, Kristen Lee Herold, 43, of Wexford on the morning of March 21 and asked her to pick up the child, according to police.

While Herold was driving Bentley to his father's home in Butler, according to investigators, the boy became unresponsive. She pulled over at a Butler shopping plaza and called 911.

Paramedics said when they got there, the boy was “bleeding excessively.”

Bentley was pronounced dead at Butler Memorial Hospital less than an hour later, police said.

Herold was arrested last week and she is charged with child endangerment, reckless endangerment and hindering apprehension.

Those charges were held for court Thursday at her preliminary hearing. She remains in the county prison on $200,000 bail.

Peters' preliminary hearing was not immediately scheduled.

Her attorney, Joseph Kecskemethy, declined to comment about the specific allegations against his client. But he said Peters respects the judicial process.

“MacKenzie understands and respects the decision of the township police and the district attorney to file the charges they filed,” he said.

“No one understands the need for accountability as it relates to the care and subsequent death of this child more than she does.”