Politico:

MSNBC may be obsessed with the four men arrested for trying to tamper with Sen. Mary Landrieu’s telephones, but the network says reporter David Shuster crossed the line when he attacked one of them via Twitter.
Just before leaving for New Orleans to cover the story, Shuster used a Twitter message to tell conservative filmmaker James O’Keefe — one of the four men arrested by the FBI — that he’s “not a journalist,” that he “intended to tap phones” and that he “will go to prison.”
“The comments were inappropriate,” an MSNBC spokesperson told POLITICO Thursday. “We have talked to David about them.”
Still, Shuster continues to cover the story for MSNBC. At 3 p.m. Thursday, he’s expected to interview Andrew Breitbart, who pays O’Keefe a salary and published his undercover anti-ACORN videos on his website Big Government.