A teen killer from West Virginia pretended to be devastated on social media over her pal’s death after she slaughtered her, according to a new report.

Sheila Eddy, then 16, fired off a series of chilling tweets before she was arrested for 16-year-old Skylar Neese’s murder in July 2012, according to a “20/20” report set to air Friday.

“Rest easy Skylar, you’ll ALWAYS be my best friend,” Eddy tweeted along with a photo montage.

Eddy allegedly lured Neese to a wooded area where she and another friend, Rachel Shoaf, stabbed her and left her to die.

For months, Neese was assumed missing until Shoaf suffered a nervous breakdown and confessed to the murder.

She allegedly told police in January 2013 they had killed their pal because “We just didn’t like her,” according to the report. Schoaf claimed they plotted the murder in science class and planned to count to three before stabbing her.

Eddy, however, still attempted to maintain appearances after Shoaf’s bombshell confession. When authorities discovered Neese’s remains, Eddy posted on social media, “worst day of my life.”

But two weeks later, she appeared to allude to murder writing, “we really did go on three.”

It wasn’t until May 1, 2013, that Eddy was arrested in connection with Neese’s death.

Both teens were charged and convicted of murder. Eddy, now 23, is serving a life sentence while Shoaf was sentenced to 30 years.