A ribbon for missing University of Iowa student Mollie Tibbetts hangs on a light post, Tuesday, Aug. 21, 2018, in Brooklyn, Iowa. Tibbetts was reported missing from her hometown in the eastern Iowa city of Brooklyn in July 2018. (AP Photo/Charlie Neibergall)

A group of Iowa conservatives appeared to fall short of the necessary signatures Saturday to add an attorney general candidate to the November ballot, an effort fueled by the arrest of a Mexican man in the slaying of missing college student Mollie Tibbetts.

Petition organizers supporting Des Moines attorney Patrick Anderson's non-party candidacy were tasked with collecting 1,500 valid signatures of registered voters from at least 10 counties.

"On a cursory look, it appears that they have not met the minimum threshold," elections assistant Wes Hicok said of the signatures the secretary of state's office received before the 5 p.m. Saturday deadline.

A formal review of the paperwork will take place Monday, he said.

Dozens of people across the state collected the signatures, but they didn't start the campaign until Wednesday — the day after Tibbetts' body was found in a cornfield and Cristhian Bahena Rivera, who is believed to be living in the country illegally, was charged in her killing.

George Anderson, Patrick Anderson's son and an organizer of the effort, said that prompted his father to try to challenge Attorney General Tom Miller, a Democrat currently running unopposed for his 10th term.

"This has to do with the upholding of immigration law," he said. "I'm not sure the current attorney general is committed to that."

Miller entered the national debate over U.S. immigration policy in June when he joined 20 other Democratic attorneys general in calling for the federal government to stop separating children from their parents when they enter the country illegally.

The 11th-hour effort could face more than the challenge of whether it collected enough signatures. State law doesn't allow non-party candidates to use any part of the Republican, Democratic or Libertarian party names — the only three parties currently recognized in Iowa. Anderson's effort plans to list "GOP" beside his name. GOP is short for "Grand Old Party" and is used interchangeably with "Republican."

George Anderson acknowledged that would likely draw objections but said he believed it would be a dispute the group could win.

News from © The Associated Press, 2018