Tia Ludwick, 24, has been ordered to spend 17 years in prison.
Ludwick was one of three people who came to Maine in October of 2016 with plans to steal marijuana from her cousin Douglas Morin.
Officials said Morin was shot and killed along a dirt road in Sherman.
Ludwick plead guilty to robbery and murder charges.
Darin Goulding also reached a deal with prosecutors in which he agreed to plead guilty to robbery.
In return, his murder charge has been dropped and Goulding will testify against Marcus Asante when he goes on trial next fall.