(CNN) -- Two petitions posted on the White House's public website over the weekend urge President Barack Obama to recommend that the Justice Department begin a federal civil rights prosecution of George Zimmerman, who was found not guilty Saturday in the Florida killing of teenager Trayvon Martin. Combined, the petitions have garnered more than 15,000 signatures since they were created on Sunday.


Additionally, a petition on the website of the NAACP urging federal action in the Zimmerman case had garnered more than 600,000 signatures as of Monday morning. That document asks Attorney General Eric Holder to "Please address the travesties of the tragic death of Trayvon Martin by acting today."

The group's website crashed for several hours Sunday between 11 a.m. ET and 1:30 p.m. ET because of the crush of people trying to respond. NAACP President and CEO Benjamin Jealous said on CNN Sunday his group had spoken with Justice Department officials about pursuing civil rights changes against Zimmerman.

Petitions posted on the White House's "We the People" site need 100,000 signatures in 30 days to elicit a response from the administration. The more popular of the two Zimmerman-related petitions, which has received more than 13,000 signatures alone, is on pace to easily reach that mark. It calls on Attorney General Eric Holder to prosecute "George Zimmerman for depriving Trayvon Martin of his Constitutional Rights of Life and Liberty."

Obama issued a statement on the verdict Sunday afternoon, less than 24 hours after the jury concluded deliberations.

"I know this case has elicited strong passions," Obama said in his statement. "And in the wake of the verdict, I know those passions may be running even higher. But we are a nation of laws, and a jury has spoken."

The Justice Department opened an investigation into the Zimmerman case earlier this year, and has been working with the FBI and Florida officials to determine if there were any violations of federal law. According to a department spokesperson, that investigation is ongoing and will now include evidence and testimony from the state's trial.

CNN's Kevin Bohn contributed to this report.

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