MADISON, Wis. (AP) — The mayors of Wisconsin’s five largest and most Democratic cities started to receive subpoenas Wednesday as part of a Republican-ordered investigation into the 2020 presidential election being led by a retired state Supreme Court justice.

Attorney Michael Gableman, in an interview Tuesday with the Milwaukee Journal Sentinel, also said he did not understand how elections work after last year claiming without evidence to supporters of Donald Trump that the election had been stolen.

Gableman issued his first round of subpoenas last week to the Wisconsin Elections Commission and officials in the cities of Milwaukee, Madison, Green Bay, Racine and Kenosha. On Tuesday night, Gableman said he also intended to subpoena the mayor of those cities and as of Wednesday afternoon those had been received in Milwaukee, Madison and Racine.

President Joe Biden won all five of those cities on his way to defeating Trump in Wisconsin by nearly 21,000 votes, an outcome that survived recounts and court rulings in both state and federal courts.

Democrats have decried the Gableman investigation as a farce and an attempt to undermine public confidence in elections. There is no evidence of widespread fraud in Wisconsin. Only four people out of about 3 million who cast ballots in the election have been charged with fraud.

Gableman spoke to the Green Bay City Council about the investigation on Tuesday night. In an interview with the Milwaukee Journal Sentinel, he also admitted to not understanding how elections work.

“Most people, myself included, do not have a comprehensive understanding or even any understanding of how elections work,” Gableman told the Journal Sentinel.

Gableman said his report would compare how the 2020 election was supposed to work versus how it did.

“Section one: What should have occurred during the election? How do these things work? Most people don’t know about that,” he told the newspaper. “Election laws are unlike, say, laws about don’t kill me — they’re not intuitive. No one can call elections laws common sense. Once you understand them, it may be common sense but it’s not intuitive. And so most people, myself included, do not have a comprehensive understanding or even any understanding of how elections work.”

Gableman did not immediately return a message from The Associated Press seeking comment Wednesday.

Gableman also said in Green Bay on Tuesday night that he does not know if he can complete his investigation by the end of October, as Republican Assembly Speaker Robin Vos said he expected it to be done. Gableman, who was hired by Vos and is being paid $11,000 a month in taxpayer money, did not say how long he thought his work would take. The total budget for the probe is $676,000.

The subpoenas Gableman has issued so far, which are signed by Vos, seek a wide array of election information, including “all documents contained in your files and/or in your custody, possession, or control pertaining to the Election.” That could amount of thousands of pages of documents, or more.

Gableman told the Journal Sentinel if the officials want to narrow down his request “I’m certainly open to doing what is efficient.”

Gableman has also told those subpoenaed to be prepared to give testimony on Oct. 15 and Oct. 22 at an office in suburban Milwaukee. Gableman told the Green Bay council that those who grant him interviews would be given immunity from prosecution.

He said he planned to look into advice the bipartisan state Elections Commission gave to clerks and donations the nonprofit Center for Tech and Civic Life gave to Wisconsin communities to help run the 2020 election.

The grants were funded by donations from Facebook founder Mark Zuckerberg. They angered some Republicans because $6.3 million went to the five Democratic cities, but Republican-heavy areas in Wisconsin also received smaller grants. Nationwide, the center gave about $350 million to communities to help make it easier to run elections during the COVID-19 pandemic.

Gableman called voting machines “an important area of inquiry” but did not say whether he would try to seize them from election officials or what his ultimate plans were for the machines.