Updated

NEW YORK -- Caroline Kennedy's spokesman decried the "mudslinging" surrounding her decision to drop her U.S. Senate bid.

A set of press reports have claimed Gov. Paterson never intended to pick the daughter of the late President Kennedy -- and, in less than a day since she withdrew her bid, FOX News has learned Paterson has selected Rep. Kirsten Gillibrand to replace Hillary Clinton in Senate.

The New York Post cited a source close to the governor saying Kennedy was "mired" in problems with her taxes, her nanny and possibly her marriage.

Kennedy spokesman Stefan Friedman issued a written statement Thursday repeating that Kennedy withdrew for "personal reasons" only.

"Any statements to the contrary are false. The governor set up a fair and deliberative selection process. This kind of mudslinging demeans that process and all those involved," Friedman said.

Meanwhile, Paterson said in a statement released Thursday that Kennedy's decision to withdraw from the race was "her's alone."

"The governor had a private conversation with Ms. Kennedy yesterday afternoon. Out of respect for her decision-making process, the governor's office did not respond to any inquiries in order to allow her time to deliberate," the statement read in part.

A Kennedy aide told FOXNews.com that Kennedy's decision was "last-minute." The aide said she dropped out of the race because of a "pressing personal matter" unrelated to the health of her uncle, Massachusetts Sen. Ted Kennedy, who is fighting a serious brain tumor and suffered a seizure Tuesday during an inaugural lunch held for President Obama.

But there have been conflicting reports on the motive behind Kennedy's decision.

The New York Times cited a source it did not identify as saying Kennedy withdrew out of concern for her uncle and his illness. And the New York Post, which was the first to report Kennedy's withdrawal from the Senate contest, cited an unidentified source saying she dropped out because she learned Paterson had decided not to choose her.

Critics had speculated that Kennedy's abrupt exit from the race boosted the chances of state Attorney General Andrew Cuomo and nearly a dozen other contenders, including Rep. Carolyn Maloney, Rep. Steve Israel and city teachers union President Randi Weingarten.

FOX News learned late Thursday evening that Rep. Gillibrand, a Democrat elected in 2006, was Paterson's choice to succeed Clinton.

Gillibrand represents the state's 20th congressional district in the U.S. House of Representatives. She is the first Democrat to represent the district since 1978 -- and the first female representative of the district, and there were media reports Thursday night that Gillibrand had been chosen by Paterson

Some New York City Democrats were skeptical of Gillibrand, who voted against the financial rescue package last fall.  And, the National Rifle Association has endorsed Gillibrand -- another cause for concern among some Democrats.

In defense of the endorsement, Gillibrand told FOX News that she come from a "hunting family" and "wants to support hunter's rights."

FOX News' Chad Pergram and the Associated Press contributed to this report.