Sherman said that the Richard family is a "typical all-American family" and that Martin and his little brother always loved to play in their yard, no matter the weather.
Neighbor Dan Aguilar told The Boston Globe the same and said he was having a hard time wrapping his mind around the child's death.
"That little boy will never come home again,'' he told the paper. "It's still unreal. I have no words. I have no words.''
While so much grieving continues, more details are emerging about Monday's bombings.
No suspects have been identified in the case, which federal authorities are classifying as an act of terrorism. It was not immediately known whether the origin of the bombings was domestic or foreign.
The intelligence community is poring through all threat reporting for any clues, U.S. counterterrorism officials told CNN. That includes any claims made on jihadist websites.
Nothing is being dismissed this early on, the officials said.