Looking at the history of Dallas City Hall corruption, in some -- but not all-- there's a pattern of a council member convicted of taking money in exchange for political support.

In 1997, there was the guilty plea of Council Member Paul Fielding, from North Dallas. Fielding had close ties to a janitorial service and pressured a large company to sign a million-dollar janitorial contract. In exchange, Fielding promised to support the large company in a zoning issue before the city.

In 2000, Council Member Al Lipscomb was convicted of taking bribes from the Yellow Cab Company. In return for $95,000 in payments, Lipscomb was convicted of providing favorable votes. Lipscomb's conviction was later overturned. A judge ruled the trial had improperly been moved out of Dallas County.

The 2008 conviction of Council Member James Fantroy was not about bribery. Federal prosecutors convicted him of embezzling $21,000 dollars from a development fund for Paul Quinn College.

And finally, there were the most-recent city-hall-corruption-cases that ended about 8 years ago...the largest in city history. A housing developer bribed Council Member Don Hill with $215,000 dollars. In exchange for the money, Hill voted for the developer's project in South Dallas.

In this most recent case, against Mayor Pro Tem Dwaine Caraway, he admitted to taking $450,000 in bribes. But there won't be a trail because he made a plea deal with prosecutors.