While I can certainly understand why many are drawing the local suspect conclusion, I want to throw out another scenario. Looking at the overhead images of the area, I was surprised to see the multi-unit structure near the corner of Boylston Rd and Rt 31 it is approx 1/4 mile from the cemetery and definitely stands out among the single family homes.
Apparently these buildings comprise a small HUD housing project. For those who are not aware, these projects house eligible residents from anywhere, not just the local area. And while this complex is for the elderly, I can tell you definitively that disabled younger folks are often housed in these complexes, too. And when I say disabled, that could mean unable to work because of a drug or alcohol addiction.
While I am not suggesting that any resident had anything to do with this, I think the presence of this complex opens the neighborhood to additional folks who may not otherwise have reason to be there. I am thinking CNAs, children, grandchildren, handymen, cleaning people, or friends from the residents previous community which may have been a shelter, jail or rehab facility.
I could see a care-giver or family member visiting the complex each Sunday to see Grandma. Visitor is accompanied by her good-for-nothing boyfriend who normally sits out in the car and smokes. It is a hot summer, his ac doesnt work so he smokes outside. Other residents have complained (or smoking is banned on property?) so he walks out to the road each Sunday to smoke. VM passes him around the same time a couple of times each month. He figures out her schedule and route and for reasons I cant even contemplate, decides to kill her. Perhaps he even drove his SUV to the cartpath earlier in the afternoon to scope it out.
Or maybe recovering drug addict resident allows his buddies from the county jail to crash in his apartment. No smoking allowed in apartment so he goes out to the road and same scenario occurs.
I know this is all very hypothetical, but I think it lays out the possibility of a suspect who is familiar with the area from regular visits, but doesnt live there.