Prosecutors in San Antonio say Alexi Estebes-Mejia pleaded no contest to murder as jury selection was to begin Tuesday. He faces up to 32 years in prison over the 2009 slaying of Juan Jose Santana-Hernandez.
A corner determined the victim had been stabbed and suffered chopping wounds allegedly caused by a machete.
Another roommate, Erlin Yobani Garcia-Rivera, reached a plea agreement Friday on a reduced charge of aggravated assault and was to testify for the prosecution. Garcia-Rivera is expected to face a maximum 20-year prison term.
Investigators say Estebes-Mejia and Garcia-Rivera blamed each other for the killing after the trio had been at a party.