She would like an investigation into the assassination of her husband.

她想要对其丈夫的遇刺进行调查。

《柯林斯英汉双解大词典》

Oh ok, I see , so the one with an "I" is actually more formal, like an investigation.

哦，知道了，那么以“”开头的比较正式，象调查。

youdao

The virus was first identified in the State Serum Institute in Copenhagen, Denmark, in 1958 during an investigation into a pox-like disease among monkeys.

1958年，在对一种猴子中出现的痘类疾病的调查中，丹麦哥本哈根的国家血清研究所首次发现了这种病毒。

youdao

He refused.Lincoln believed that starting an investigation would be like lighting a barrel of gunpowder.

VOA: special.2009.10.29

They like an investigation that can't begin, so you have the charges out there that can't be proven or disproven.

NPR: Ethics Panel Astir on DeLay, Rules

That could limit cases like de Soto where an investigation tracks not just the suspect, but every contact that suspect has ever called.

FORBES: Court Throws The Book At Warrantless Cell Phone Tracking

Thus, like most employers conducting an internal investigation, Harvard was not prohibited from conducting its e-mail search.

FORBES: Harvard's Secret E-Mail Search: The Intersection of Internal Investigations and Digital Privacy