By Ian Simpson
WASHINGTON, March 26 (Reuters) - A campaign finance scandal in the District of Columbia has made next week's Washington Democratic mayoral primary a dead heat, dissolving embattled incumbent Vincent Gray's lead, a poll showed on Wednesday
Gray, who federal prosecutors have linked to corruption charges, trails city council member Muriel Bowser, with polls showing the challenger having the support of 30 percent of likely Democratic primary voters and the incumbent just 27 percent, the Washington Post survey showed.
Support for Bowser has more than doubled since a January Post poll, while Gray's backing is unchanged. Eight candidates are running in the mayoral primary and winning that contest is seen as tantamount to winning the general election in the heavily Democratic U.S. capital.
Gray's reputation was tarnished this month when D.C. businessman Jeffrey Thompson, a former government contractor, pleaded guilty to violating campaign finance laws. Federal prosecutors had accused him of funneling more than $660,000 through friends and relatives to Gray's successful 2010 campaign.
Prosecutors say Gray agreed to refer to Thompson as "Uncle Earl" in fundraising conversations to conceal the activities.
Gray, who has presided over an economic boom, improved schools and a drop in the city's murder rate to a 50-year low, has denied anything illegal took place.
Both Gray and Bowser are black, but Gray has more support in largely black wards, according to the Post poll.
The newspaper's survey showed that 49 percent of likely primary voters said the corruption probe would be a major factor in their vote, up from 43 percent in January.
The winner of the Democratic primary will face David Catania, an openly gay independent member of the city council, as the leading challenger in November.
A poll question about possible general election matchups showed Catania and Gray tied with 41 percent support, while a hypothetical matchup between Bowser and Catania showed the Democrat with a 30-point lead.
The Post polled 661 likely voters from March 20 to 23. The poll has a margin of error of 4 percentage points, meaning results could vary by that much either way. (Reporting by Ian Simpson; Editing by Scott Malone and Jonathan Oatis)