All Suspects Form a Chain
All Suspects (or Innocents) within the named group form a single connected component under 4-neighbor (orthogonal) adjacency. In a linear group such as a row or column, this simply means the Suspects occupy a contiguous block with no gaps. The clue implicitly requires at least 2 Suspects in the group (a single cell is trivially connected and not informative enough to generate). When you know both the count and the connectivity requirement, the valid placements are only the contiguous sub-segments of that length — far fewer than the unrestricted count would suggest.
Reading the examples
“All suspects in row 1 are neighboring to each other”
The clue says all suspects in row 1 are neighboring to each other. Given the revealed cells, the adjacency requirement forces Alice (Suspect).
“All suspects in column A are neighboring to each other”
The clue says all suspects in column A are neighboring to each other. Given the revealed cells, the adjacency requirement forces Alice (Suspect).
“All suspects in Y's neighbors are neighboring to each other”
The clue says all suspects in Eve's neighbors are neighboring to each other. Given the revealed cells, the adjacency requirement forces Frank (Innocent), Henry (Innocent), Iris (Innocent).
“All suspects in the edge are neighboring to each other”
The clue says all suspects in the edge are neighboring to each other. Given the revealed cells, the adjacency requirement forces Grace (Innocent), Henry (Innocent), Iris (Innocent).
“All suspects to the left of Y are neighboring to each other”
The clue says all suspects in to the left of Frank are neighboring to each other. Given the revealed cells, the adjacency requirement forces Diana (Suspect), Eve (Suspect).