A construction contractor with deep connections in the Atlanta government has been accused of paying more than $1 million in bribes to win city contracts. After his expected guilty plea, he could become federal prosecutors’ star witness in a corruption case now gripping City Hall, legal experts say.

But 16 months ago, somebody wanted him to keep quiet, because he was already talking to the feds, The Atlanta Journal-Constitution and Channel 2 Action News have learned.

An ominous message, left at contractor E.R. Mitchell Jr.’s Southwest Atlanta home, bluntly stated that he needed to keep his mouth shut. An even more potent message left on Mitchell’s property seemed to threaten his life.

"You only hear about this kind of thing in movies," said William Perry, head of Georgia Ethics Watchdogs. "For this to happen in real life shows that there are some pretty desperate people trying to keep this quiet. And obviously, it could be people with political futures."

Charging documents filed in U.S. District Court in Atlanta this week say Mitchell conspired with someone in the construction industry to pay bribes to another unnamed person connected to the city. The documents say Mitchell believed some of the money would go to one or more city officials with influence over government contracts.

No other suspects have been identified, and Atlanta Mayor Kasim Reed says the city is cooperating with the federal probe.

Read details about the case and the threats on Mitchell in today's story at MyAJC.com.