Michael Pelkey, 62, grew up in Millinocket and lived in Maine before moving to New Mexico 15 years ago.
He worked at a local gas station in the town of Edgewood and became loved by people in the community.
They were shocked and outraged when he was gunned down February 11 after confronting a robber who had taken money from the cash register.
Police said seven people planned the robbery and were watching as one of them carried it out.
Six of the suspects were arrested over the weekend and the final suspect was apprehended last night.
Hundreds of people also gathered for a vigil to pay tribute to Pelkey as well as members of his family.