UPDATE: Lancaster County District Attorney, Craig Stedman says Thursday was one of the darkest days in Lancaster County. He says the family knew the suspect and called him, "Pie."
Stedman says Thomas was arrested in April and charged with sexual assault against one of the victims and another girl. He was presumed innocent but Stedman says his previous sexual assault charges could have led him to the stabbings.
Police say canines used the scent of blood from in the victims' home to track the suspect's scent at his nearby home.
DA Stedman says this case is a "hallmark for the death penalty."
UPDATE: We now know the name of the man accused of killing a woman and her teenage daughter Thursday morning in Lancaster County.
EAST DRUMORE TOWNSHIP, Pa. -- Police say Leeton Thomas stabbed Lisa Scheetz and her 16 year old daughter to death inside of a home in East Drumore Township along the 800 Block of Spring Valley Road.
Police found them dead in the basement.
EMS took Scheetz' other teenage daughter to the hospital, she is listed in stable condition.
She is initially called police around 2:30 in the morning.
Police arrested Thomas at his home in Quarryville, Lancaster County on Thursday.
He is now facing criminal homicide charges.
Pennsylvania state police will be holding a press conference at eight o'clock Friday morning.
FOX43 will have a crew there and will bring you the latest details on this story.
A suspect was taken into custody Thursday for a series of stabbings at a home that resulted in the deaths of a 44-year-old woman and her 16-year-old daughter and left a 15-year-old daughter critically injured.
Police received a call from the 15-year-old around 2:20 a.m. Thursday, saying she had been attacked in a home on the 800 block of Spring Valley Road.
"It's a tragic event," Tpr. Samantha Minnucci, with the Pennsylvania State Police, said. "Unfortunately, we had to respond to it and we will do the best that we can to seek justice for this."
Investigators scoured the area for clues, calling in K-9 units to search for evidence in a wide rural area to piece together what happened.
"We are trained to handle this, and we are used to this area, for this is the area we patrol all the time," Minnucci said.
The girl was rushed to Lancaster General Hospital in critical but stable condition. Police then found her mother and sister dead in the basement. Officials have not identified the victims nor the suspect taken into custody.
"At this time, we do not believe that the public is at risk at all," Minnucci said. "We do believe that the victims knew the suspect."
Residents described their neighborhood as a tight-knit, quiet community where everyone has their space.
"I never knew the home existed," Karen Goddard, a neighbor, said. "It's back in the woods and never knew it was there."
"Yeah it was kind of surprising, especially when it's in your own backyard, and it's a rural community," Herb Weaver, another neighbor, said.