Dutchman Joran Van der Sloot, 24, has confessed to a court in Peru that he killed 21-year-old business student Stephany Flores in Lima in 2010
He offered a "sincere confession", which could carry a lesser prison sentence than an outright guilty plea.
Mr Van der Sloot, was arrested but never charged over the disappearance of Alabama teenager Natalee Holloway in Aruba in 2005.
The trial began on Friday but was adjourned in the wake of his plea.
The trial will resume on Wednesday when the defence will be able to respond to prosecutors' charges.
Police say Mr Van der Sloot admitted to strangling Flores on 30 May 2010 after he found her looking at his laptop in his hotel room. The laptop contained information about the Holloway case.
Mr Van der Sloot fled to Chile in the wake of Flores' death, but was later arrested and returned to Peru. His 2010 confession came after three days of questioning, officials said.
Prosecutors initially sought a life sentence for Mr Van der Sloot but are now pressing for a 30-year term.
Mr Van der Sloot was a suspect after the Holloway's disappearance on the Dutch Caribbean island of Aruba in 2005.
source: BBC News
