SALINAS, Calif. -- A woman accused of injecting women with fake Botox has been charged with murder.

Martha Vasquez has been booked into the Monterey County Jail in lieu of a $1 million bond. She is accused of killing Olivia Castillo in November last year.

Investigators said Vasquez, a hair stylist, injected Castillo in the buttocks with what authorities said is believed to have been cooking oil. Castillo died a few days later.

Vasquez was originally charged with involuntary manslaughter and practicing medicine without a license.

But since this case first broke, authorities said witnesses have come forward who also got injections that made them sick and sent them to hospitals.

Authorities also said Vasquez knew she was making people sick long before she injected Castillo.