You sometimes still hear Trump supporting Republicans pointless and nonsensical claim that there was no investigation before Trump’s second impeachment trial.
With all the first hand evidence they had, and provided at the impeachment trial, what further investigation was needed?
With the evidence they had, they proved that Trump should be held accountable for his role in inciting the events of January 6th.
Listen to how Trump and his supporting Republicans are "now" trying to present what happened on Jan 6th, “They were peaceful people, these were great people ... the love in the air, I've never seen anything like it”, compare that to McConnell’s description.
Here is part of the transcript from Republican Mitch McConnell’s conclusion right after the trial.
”January 6th was a disgrace. American citizens attacked their own government. They use terrorism to try to stop a specific piece of domestic business they did not like. Fellow Americans beat and bloodied our own police. They stormed the center floor. They tried to hunt down the Speaker of the House. They built a gallows and chatted about murdering the vice president. They did this because they’d been fed wild, falsehoods by the most powerful man on earth because he was angry. He lost an election. Former President Trump’s actions preceded the riot or a disgraceful dereliction of duty. The House accused the former president of quote “Incitement”. That is a specific term from the criminal law. Let me just put that aside for a moment and reiterate something I said weeks ago. There’s no question, none, that President Trump is practically and morally responsible for provoking the events of the day. No question about it.”
Now we all want an investigation to see if "criminal charges" should be brought against Trump, and the same Republicans are doing all they can to insure that such an investigation doesn't take place.