A Wisconsin teenager allegedly wrote about killing in an online blog before she murdered her mother and stepfather and fled the state.

Ashlee Martinson, 17, was arrested Sunday for the deaths of Thomas and Jennifer Ayers in Boone County, Ind., where she and her boyfriend were apprehended after county sheriff's deputies stopped them on a highway, WISH-TV reported.

Under the alias VampChick, Martinson allegedly created a blog named Nightmare and described murder scenes in appalling detail.

"Another has just departed this life forever, and what a better world it shall be as soon as I eliminate filth who are unworthy of life, just like she was," reads a line in the blog dated March 2, according to the station.

Six days later, 37-year-old Thomas Ayer was found shot to death upstairs at his home in Rhinelander, Wis. His wife Jennifer, 40, was found stabbed to death. Police were called to the scene Sunday morning after receiving a 911 call from a girl who said her father was dead and "his head was cracked open," according to court documents obtained by the station.

Three girls ages 2, 8 and 9 were found alive at the home.

After allegedly killing her parents, Martinson, the girls' older sister, told them they were "going to play a game" and locked all three in a room with juice and food, the 9-year-old told police.  

Martinson then fled the home with her 22-year-old boyfriend, Ryan Sisco. Police believe the two were headed for Tennessee before they were caught, WISH-TV reported.

Sisco was also arrested but the charges against him have not been released. Martinson, believed to have acted alone, is charged with two counts of intentional homicide and remains held in Boone County jail.