I've been investigating the company but there is little information about it.
- to inquire into (a situation or problem) thoroughly; examine systematically, esp. in order to discover the truth (Collins Dictionary)
Investigating is often associated with officials searching into an event, a situation or a claim so as to learn some facts about it.
However, the sentence above is about someone looking for information about a company, trying to find out more about it (before an interview). Investigate doesn't seem to be the right word in this context. Which alternatives would be better?