A man who entered an unlocked Kapiolani Boulevard apartment and fatally stabbed a 27-year-old woman with a kitchen knife he found in the apartment pleaded guilty this afternoon to murder and other charges.

Sato Franklin Sigrah, 21, pleaded guilty to second-degree murder, first-degree burglary and two counts of first-degree assault in a plea deal with the prosecutor. Trial was scheduled for next week.

Sigrah faces a mandatory life prison term with the possibility of parole when a state judge sentences him in July.

In exchange for his guilty pleas the prosecutor agreed to drop an attempted first-degree murder charge and reduced two attempted second-degree murder charges to first-degree assault. First-degree murder carries a mandatory penalty of life in prison without the opportunity for parole.

Sigrah fatally stabbed 27-year-old Lyola Mesebeluu Oct. 11, 2008, and then stabbed Mesebeluu’s husband and daughter.

Police said Sigrah entered the Mesebeluus’ apartment after testing the front doors of other apartments in the complex. They said they believe Sigrah didn’t even know his victims.

Sigrah told police he doesn’t remember what happened because he blacked out. He said he drank three beers and at least half of a 1.75-liter bottle of vodka after work hours earlier.

The state said Sigrah’s blood alcohol content two-and-a-half hours after the stabbing was 0.19, more than twice the legal threshhold for drunken driving.