1. To examine or inquire into something thoroughly and in detail, going beyond surface-level analysis
The detective decided to investigate deeply into the mysterious disappearance.
O detetive decidiu investigar profundamente o desaparecimento misterioso.
2. To conduct a comprehensive examination or study of a subject with great care and attention
Researchers investigate deeply into climate change causes.
Os pesquisadores investigam profundamente as causas das mudanças climáticas.