By Brian Maass and Mark Ackerman

DENVER (CBS4)– An ongoing CBS4 voter fraud investigation has uncovered a dozen cases where Coloradans are suspected of voting twice. Previous CBS4 Investigations revealed ballots cast in the names of Coloradans who had been dead for months– sometimes years- before votes were cast in their names.

In six of the new cases, voting records show the same people voting twice in Colorado elections. In another six cases, people are suspected of voting in Colorado and another state during the same election cycle.

Lincoln Wilson, a registered Republican from Hale, in Northeast Colorado, is accused of voting in both Colorado and Kansas in 2010, 2012 and again in 2014. Wilson told CBS4 he voted in both states, but only “voted on local issues” and “didn’t vote twice for President.”

Wilson is one of five Coloradans now charged by the State of Kansas for voting in both states.

Randall Killian, an unaffiliated voter, pleaded guilty to voting in Douglas County, Colorado and Kansas in the 2012 presidential election. Ron Weems, a registered Democrat, pleaded guilty to voting in Teller County, Colorado and Kansas in both 2012 and 2014. Both men were fined for their offenses.

Kansas has also charged James Criswell, a Republican from Douglas County, and Sharon Farris, a Republican from Denver, with double voting. Their cases have not been resolved yet.

“You’d be surprised how often people double vote,“ said Kansas Secretary of State Kris Kobach. “Two of the cases are serial double voters. I think people discover they can get away with it and keep doing it.”

Kobach says his office is “aggressively prosecuting” double voting cases because it’s a crime that “can’t be caught ahead of time.”

He says after each election, Colorado and Kansas crosscheck voters to identify double ballots and clean up their databases. But Kobach still believes 10,000 people are registered to vote in both Colorado and Kansas.

“Any one of those 10,000 people could probably succeed in casting two votes,“ Kobach said. “We want to get the word out, ‘Don’t do it, we’ll catch you.’”

Colorado and Kansas are two of 28 states that share voting data as part of the Interstate Crosscheck program. Colorado also shares voter data with 10 other states in a different program, called Electronic Registration Information Center, or ERIC.

Florida doesn’t participate in either data sharing project.

CBS4 compared absentee ballots from Florida with Colorado’s voter rolls and found a suspected double voter with residences in Colorado Springs and Titusville, Florida. The El Paso County Clerk has forwarded that case to prosecutors for review.

“Some states haven’t recognized the importance of participating in ERIC and making sure the integrity of the process is ensured,” said Colorado Secretary of State Wayne Williams.

Yet, some people, like Bruce Rickey, are being prosecuted for voting twice in Colorado. Rickey, who is a registered Republican, was charged with trying to vote twice in the 2015 Colorado election. Prosecutors say Rickey voted in El Paso County where he lived, and then allegedly tried to vote in Elbert County as well. Court documents say Rickey “hated” the Elbert County sheriff and told an election official he wanted to vote against the sheriff on a term limit issue.

“There are individuals who break the law and they should, and are, being prosecuted for that,” said Williams.

But, Williams admits other Coloradans are getting away with it. Combing through voter data, CBS4 found three suspected double voters in Denver, one suspected double voter in Arapahoe County and one suspected double voter in Douglas County. All five cases that CBS4 uncovered have now been referred to prosecutors for possible criminal action.

“It’s a relatively small number,” said Williams, “But, it is a problem of any magnitude because we have close elections in Colorado.”

Williams said people can show up twice on Colorado’s voter rolls if their information is slightly different, due to a change of address, a change of name through marriage, or a simple typo.

Since ballots were mailed out last week, CBS4 has been contacted by a handful of voters who have received more than one ballot.

Teresa Hailey, from Northeast Denver, said she received two ballots, one sent to her home address, the other to her P.O. Box.

“I want someone to take this very seriously,” said Hailey who was confused about which ballot to cast.

Alton Dillard, spokesperson for the Denver Elections Division, said Hailey made a late change to her registration, which triggered a replacement ballot to be mailed to her.

“Once the second ballot was sent, the first one was voided. Even if she attempted to vote twice the system would have flagged the problem,” said Dillard.

Denver has a special elections phone line set up to answer any questions that arise. Denver residents can call 311 to reach the special elections operators.

CBS4 Investigator Brian Maass has been with the station more than 30 years uncovering waste, fraud and corruption. Follow him on Twitter @Briancbs4.

Mark Ackerman is a Special Projects Producer at CBS4. Follow him on Twitter @ackermanmark