unsub
n.— «Unsub is shorthand for “unknown subject,” meaning the person believed to have committed the crimes. Nor is it new. There was a 1989 series called Unsub, which followed a government unit investigating serial killers.» —“‘Unsub’ unmasked and other TV queries” by R.D. Heldenfels Akron Beacon Journal (Ohio) Apr. 6, 2006. (source: Double-Tongued Dictionary)
Further reading
What kind of book do people ask for most often in prison? Romance novels? No. The Bible? No. The most requested books by far are … dictionaries! A number of volunteer organizations gather and distribute used dictionaries to help inmates with...
Grant recommends the children’s book Dreams of Green: A Three Kings’ Day Story written by Mariel Jungkunz and illustrated by Mónica Paola Rodriguez (Bookshop|Amazon), about a girl and her family who move from Puerto Rico to Ohio and find ways...