Investigated deeply

• Looked into
• Professional with education degree asked searching questions
• Asked searching questions — minor problem with editor
• Searched hard for somewhere to sleep
• Searched for somewhere to sleep
• Delved into
• Examined closely

Wiktionary Word definitions in Wiktionary
vb. (en-past of: probe )

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Probe \Probe\, v. t. [imp. & p. p. Probed ; p. pr. & vb. n. Probing .] [L. probare to try, examine. See Prove .] To examine, as a wound, an ulcer, or some cavity of the body, with a probe. Fig.: to search to the bottom; to scrutinize or examine thoroughly. ...