RALEIGH, N.C. (AP) — Changes made to absentee voting procedures five years ago in North Carolina may have emboldened workers to run the type of illegal “ballot-harvesting” operation alleged to have been used in a disputed congressional race, election experts and lawmakers said.

Some observers are concerned that the changes made it possible for more people to apply for absentee ballots. Then so-called harvesters could collect unsealed ballots and manipulate them or throw out ones from minority voters who might have otherwise gone to the polls.

The heavily Republican Legislature crafted the 2013 law that scaled back some voting options amid a national GOP push for voter ID laws and other restrictions they said were aimed at preventing in-person voting fraud, which experts say is rare. Many provisions were struck down in court, but unchallenged absentee changes may have opened wider a door to possible widespread fraud.

“It could have exacerbated the problem,” Republican state Sen. Tommy Tucker said this week. He and other state legislators believe more absentee ballot restrictions may be necessary.

Investigators are scrutinizing mail-in ballot requests and ballot envelopes in the 9th Congressional District — a process that could lead to criminal charges or even a new election. Republican Mark Harris leads Democrat Dan McCready by 905 votes out of nearly 283,000 cast. The focus appears to be on Bladen and Robeson counties.

Since the 2013 law was approved, a decades-old political practice in which workers are paid to get people to vote by mail “became more visible,” Robeson elections board Chairman Steve Stone said, particularly after the law eliminated their access to nursing homes. Unfettered access to blank ballot request forms also likely helped.

“When you have these people that possibly are getting paid a bounty per registration or per voter, then they’re limited and can’t go to the facilities, they are going to go out in the neighborhood to do it,” Stone said in an interview.

Before 2013, voters had to submit a handwritten request for an absentee ballot or call to receive a form generated by each county board office. The person filled out the ballot in the presence of a witness. The voter and the witness had to sign the envelope, which was either mailed or taken in person by the voter, a near relative or a legal guardian.

The 2013 law ended the letter requirement and created a statewide ballot-request form that had to be filled out. The form, which is posted online, could be used in any county and could be reprinted, making it easier for political parties, interest groups and broad get-out-the-vote efforts to recruit people to request mail-in ballots.

But the law also required applicants to provide more information on those requests to prove their identity, including a driver’s license number or the last four digits of a Social Security number. And the envelope containing the completed ballot now had to be signed by two witnesses or a notary public.

In all, 104,000 people voted by mail this fall in North Carolina.

McCrae Dowless, a contractor for the Harris campaign’s chief strategy firm, is listed as one of the top collectors of absentee ballot requests turned in to the Bladen County elections office. Collecting requests is lawful and done by both major parties. The election board now calls Dowless a “person of interest” in its investigation. He’s been mentioned in ballot operations going back to at least 2014.

Election officials and prosecutors are looking at whether political operatives collected absentee ballots from voters but did not deliver them to county board offices. Some affidavits suggest voters received absentee ballot applications they never requested or were met by workers at their homes who took ballots that were either not completed or not placed in a sealed envelope. Those activities are illegal.

The law also attempted to rein in situations where nursing home operators were helping patients fill out ballot requests or the ballots themselves, or bringing in a campaign or party to do so. Now a team from the county election board will come in to help if a relative is not available.

Brad Crone, a longtime Democratic consultant in North Carolina, said improved access to request forms is positive, and he doesn’t see the 2013 law as the problem. “The abuse comes in when you send campaign staff out to collect completed ballots or uncompleted ballots. That’s where you cross the line.”

It’s also possible that absentee ballot activities simply turned more brazen because they have rarely been prosecuted. Gary Bartlett, the state elections director for 20 years until 2013, said his office referred absentee ballot fraud cases in at least six counties to local prosecutors, but nothing became of them.

North Carolina legislators have already acted on absentee ballot security. When GOP lawmakers passed a law this week implementing a new photo ID requirement, they also directed state election officials to makes rules so mail-in ballot users meet a similar ID standard.

State House Minority Leader Darren Jackson said the state should revert to the pre-2013 law and accept ballot requests only from individuals to lessen the risk for fraud.

GOP Sen. Dan Bishop said he hopes a bipartisan task force will be created to look at Bladen County’s absentee ballot issues and come up with some alterations to the rules.

“I think we’re seeing shortcomings of some kind,” Bishop said, “and they need to be dealt with.”