Cause alarm, as I've done with Du Tompes? (3,3,3,5,3,7)

I believe the answer is:

put the cat among the pigeons

'cause alarm' is the definition.
(put the cat among the pigeons means cause trouble)

I don't understand the remainder of the clue.

(Another definition for put the cat among the pigeons that I've seen is " cause a flutter in the dovecot".)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app