"The whole birther movement was racist," Powell wrote. "That's what the 99 (percent) believe. When Trump couldn't keep that up, he said he also wanted to see if the (birth) certificate noted that he was a Muslim."
Powell told The Daily Caller he was unaware his personal Gmail account had been hacked. However Peggy Cifrino, a Powell aide, confirmed to CNN that the emails are accurate.
At a meeting last December with business leaders in Texas, Powell blamed Trump's rise on the media "because he's great reality television," the Dallas Business Journal reported.
"So, what do you think we should do?" he asked. "Start to ignore him, and let's see if he has the merit to be a candidate as opposed to just the reality television spectacular."
He reiterated those sentiments in an email sent that same month to CNN's Fareed Zakaria.
"You guys are playing his game, you are his oxygen," Powell wrote.
In an interview in March on CBS This Morning, Powell said the race for the GOP presidential nomination, which was undecided at the time, had "gone into the mud."
He did not target any specific candidate for his criticism.
"The comments they're making toward each other, the nastiness, it's running us into the ground," he said. "The foreigners of the world looking at this are distressed."