After reviewing a particular piece of video evidence, investigators may have identified a suspect in the bombings at Monday's Boston Marathon.

CNN is reporting (exclusively, at the moment) that a federal law-enforcement source says that footage from a department store camera near where the second explosion occurred may have led to a major breakthrough.

Nothing official has been announced yet—meaning, no names have been released and no arrests have been made.

This post will be updated as more information comes in.

[CNN]