Democrat Ron Barber announced Thursday that his campaign has raised over $500,000 in his bid to finish former Rep. Gabrielle Giffords' term in the U.S. House of Representatives.

Barber, a former Giffords aide who was shot twice during the January 2011 assassination attempt that left the Arizona Democratic congresswoman critically injured, announced his plan to run in the special election in February.

"I believe that fundraising isn't just about the bottom line," Barber said in a statement Thursday. "It's about people investing in someone they know will stand up for their values."

According to the statement, 3,293 individuals have contributed to Barber's campaign so far.

The special election, which Arizona Gov. Jan Brewer (R) ordered after Giffords retired in January, will be held on June 12, with primary contests scheduled for April 17. While Barber faces no challengers in the Democratic primary, there are four Republicans vying to finish Giffords' term. One of those Republicans is Jesse Kelly, who narrowly lost to Giffords in 2010.

Barber has also said he plans to run for a full term in November's regular election.

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