To study closely or systematically
To go into or through for the purpose of making discoveries or acquiring information
I promised you I'd investigate this as thoroughly as I could.
He gave orders to investigate the matter.
Police are continuing to investigate while a search for the body is underway.
Giddon had barely left the yard on Diablo and Lisa instantly recognized it as a chance to investigate the building.
Later she discovered that Alice had made the call when she went to investigate why Lori's car was there.