in flagrante delicto
Concise Oxford English Dictionary © 2008 Oxford University Press:
in flagrante delicto /ɪn fləˌgranteɪ dɪˈlɪktəʊ, fləˌgranti/
▶adverb in the very act of wrongdoing, especially in an act of sexual misconduct.
– origin L., ‘in the heat of the crime’ (lit. ‘in blazing crime’).
'in flagrante delicto' also found in these Oxford entries:

