Synonyms for «deeper investigation»

Synonyms for individual words can be found below.

Case studies usually require deep investigation of the subject and thorough understanding of the matter. (advancedwriters.com)
And of course I relied on my own experience of more than 10 years of deep investigation into nutrition and health. (healthybabycode.com)
This is a puzzle that calls for deeper investigation. (blog.politics.ox.ac.uk)
(see all sentences)