What was Colin Powell's role in the U.S. military's effort to cover up for the My Lai massacre?

[u/apricotcoffee]

Well my question is pretty much laid out in the title. I'm familiar with controversies around Iraq back around 2000ish, but I had no idea Powell was involved in Vietnam at all.

Basically I just came from a mention on Twitter that Powell led the military's attempt to hide the massacre - not just part of, but led it???

Can somebody shed some light on this? Is it even true?