Kansas Secretary of State Kris Kobach speaks to a Kansas House committee Monday, Jan. 25, 2016.

Topeka ? Kansas Secretary of State Kris Kobach said Monday that records show as many as 19 non-U.S. citizens have either registered to vote or attempted to do so, but his office has not yet prosecuted any of them, either because the statute of limitations has run out, or because other cases are being given higher priority.

Kobach told the House Elections Committee Monday that those individuals have been identified by election officials in Sedgwick County who have attended naturalization ceremonies for immigrants receiving their U.S. citizenship, offered to register them to vote, and cross-checked those names against the county’s existing list of registered voters.

“And in so doing, they are coming across a surprising number of people who were already registered as green card holders and got registered, in some cases many years ago, and only now have become citizens,” he said.

But Rep. John Carmichael of Wichita, the ranking Democrat on the panel, said he recalled Kobach estimating as recently as a year ago that the number was much higher.

“As I recall your testimony before the committee last year, you told us approximately 2,200 noncitizens were registered in Kansas, and that was based upon a study you couldn’t release to us because it was preliminary,” Carmichael said.

“I don’t recall giving you a personal estimate,” Kobach replied. “I think I was extrapolating from a study or article that I had read.”

Kobach’s appearance before the committee Monday came just a few days after his office filed charges against three more individuals in Kansas for allegedly casting ballots in two different states during the same election.

Those individuals are Randall Killian of Ellis County, Ron Weems of Sedgwick County, and Michael L. Hannum of Johnson County. The charges against Weems and Hannum include felony charges for allegedly making false statements when they signed poll books in their counties. Killian is charged with misdemeanor counts of casting multiple ballots in the November 2012 election and making a false statement to obtain an advance ballot.

The possibility of non-U.S. citizens voting in Kansas elections was the main rationale Kobach offered in 2011 when he pushed for passage of a law requiring new voters to show proof of U.S. citizenship in order to register. The law took effect in 2013.

Since then, more than 30,000 would-be voters have had their registration applications placed “in suspense” for failing to produce such documentation. And in September, Kobach’s office issued a new regulation directing county election officers to begin purging the rolls of all incomplete applications that have been pending more than 90 days.

There are slightly more than 1.7 million registered voters in Kansas.

In 2014, lawmakers passed another bill giving Kobach’s office the power to prosecute voting fraud cases. Since then, only six cases have been filed, including the three new ones last week, but none of them has involved non-U.S. citizens registering to vote or casting ballots illegally.

“Right now we’re trying to do this with existing staff, so we’re going after the older cases and the cases where we have the evidence right here and it’s ready to go,” Kobach said.

Prosecuting the crime of voting by noncitizens, he said, is more difficult because in many cases the actual crime, registering to vote, occurred so long ago that the statute of limitations has expired, and because it is more difficult to gather documents and testimony to prove that someone was not a citizen at the time he or she registered.

Also at the meeting, Kobach requested introduction of a bill that would require audits of all elections, starting in 2017.

That bill is a response to recent requests by a Wichita State University mathematician, Beth Clarkson, who has wanted to audit the paper records of electronic voting machines in Sedgwick County, saying that she believes there were anomalies in that county during the 2014 elections. Kobach’s office has denied that request, saying it is specifically prohibited under current Kansas law.

Meanwhile, Rep. John Alcala, D-Topeka, introduced another bill in the committee calling for same-day registration, which would allow voters to register at any time before an election, up to and including Election Day. A copy of that bill was not available Monday afternoon.

According to the National Conference of State Legislatures, 10 other states and the District of Columbia currently allow same-day registration. Hawaii will begin offering it in 2018. Kobach has said previously that he would oppose such a law in Kansas.