Skylar Neese Update: W.Va. teenage girl pleads guilty in the death of 16-year-old "friend"

(CBS/AP) MORGANTOWN, W.Va. - Federal officials say West Virginia teen Rachel Shoaf pleaded guilty to second degree murder Wednesday in the death of 16-year-old Skylar Neese of Star City last summer.

Neese's remains were found in Wayne Township, Pa., in January. She sneaked out of her parent's apartment last July and was initially considered a runaway, but her parents soon suspected she was abducted.

Dave Neese, the victim's father, was shocked when he found out Shoaf admitted to killing his daughter. According to West Virginia Metro News, the father was surprised because the two girls, along with a third teen involved, were always together. The three girls were thought to be best friends and went to University High School together.

The paper reports that Shoaf admitted stabbing Skylar to death the night of her disappearance. However, a reasonable explanation on what exactly happened and why it happened is still missing.

According to the paper, authorities are saying very little about the investigation, giving virtually no details of the case.

Shoaf's family released a statement through their attorney David Straface, saying her crime is "unforgivable and inexcusable."

Other relatives of Shoaf say they were shocked to learn of her involvement in Neese's death and their hearts are broken for the victim's family.

Dave Neese told CBS affiliate WDTV, "It's so heartbreaking that not only did we lose our daughter, but they have lost theirs too."

U.S. Attorney William Ihlenfeld says a second teenager is in custody, but she hasn't been named and the charges weren't immediately available. He declined any further comment.

Skylar Neese was an honors student at her High School. In February, her parents celebrated her 17th birthday holding a candlelight vigil with family members, friends and strangers.

Shoaf will remain in custody until her sentencing

Complete coverage of Skylar Neese murder case