Are you really going to investigate the truth?
The true motive behind Koichi's strange words and deeds have not yet been brought to light.
One of the classes I’m taking in college is currently investigating whether the chicken or the egg came first.
When you brighten your research it's like you're shedding light on it. To do that, you have to perform an investigation.
This word is particularly used in academic and scientific situations.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.