The word is spelled thefts, just as you spelled it.
Thieves would be the plural noun, or the persons committing the thefts.
the hardest word to spell is: perpondickulor
The phrase "spike in thefts" is a noun phrase. It indicates a sudden increase in thefts. If you have a graph of thefts, you would see a sudden rise in the line, which would look something like an actual spike (which is a pointy object resembling an extremely large nail).
The Spanish word for "spell" (as in letters in a word) is "deletrear" Which translated lyerally means to separate the letters. The word for "spell" (as in time) is "temporada". The word for "spell" (as in hex) is "encanto".
The letters spell the word geometrical.
The letters spell the word casino.
The letters spell the word "freelance."
What word does these notes on the staff spell?
Those letters will spell the word vinegar.
The letters can spell the word publications (or No, a publicist!).
The word is spelled "fascinating". There is a "c".
The letters APTRUSIS spell the word "upstairs."
Unscrambled, the letters 'cureed' spell the word reduce.