Three people who plotted the murder of a developmentally disabled Wal-Mart cashier for making romantic advances on a co-worker say they're guilty.

Eighteen-year-old Amber Talbot, 24-year-old Timothy Smith and 19-year-old Anthony Howe pleaded guilty in a New Hampshire court Monday for the 2008 slaying of Christopher Gray. Police say Gray was stabbed and strangled as part of a murder plot hatched after Talbot told her boyfriend Gray had been hitting on her at the store in Woodsville.

The boyfriend, 19-year-old Michael Robie, is charged with conspiracy to commit murder and is awaiting trial.

Under the pleas, Talbot would serve 23 to 50 years in prison and Smith and Howe both 40 to life.

Gray's family members say the three deserve life prison terms.