The attorney for Joran van der Sloot says his client will plead guilty, but plans to claim temporary insanity in order to get a shorter sentence.
His lawyer says Van der Sloot killed Stephany Flores, 21, last may after she learned of his relationship to Holloway by looking at his laptop.
The 23-year-old Dutchman is accused of first-degree murder, which carries a 15- to 35-year sentence on conviction.
The "violent emotion" plea is typically used in Peru for crimes of passion
If the plea is accepted, Van der Sloot could be sentenced to three to five years in prison.
The Associated Press contributed to this report.