The New Georgia Project will go right up to Friday’s deadline to turn over thousands of documents to Georgia Secretary of State Brian Kemp as his office upped to 15 the number of counties involved in an investigation into allegations of voter registration fraud.

Investigators have also increased to 33 the number of confirmed cases of forged voter applications they say workers from the Democratic-backed group submitted. The expanded inquiry comes as local officials continue to sift through new voter forms ahead of the state’s Oct. 6 registration deadline.

Kemp's office confirmed Thursday that it has been in contact with the group's leaders several times after an extraordinary Georgia Election Board meeting last week, in which investigators acknowledged a then-25 confirmed forgeries among more than 85,000 registration forms submitted by the group since March.

Chief investigator Chris Harvey and a lawyer for the Secretary of State’s Office sat down with leaders Monday in their office, and both sides have exchanged several phone calls to work through issues related to a subpoena originally issued by Kemp’s office Sept. 9.

What amounts to a cooling-off period came after heated comments last week ahead of the board meeting. Supporters of the New Georgia Project accused Kemp of voter suppression and suggested he may be stalling the registration process for thousands of would-be voters for fear they may support Democratic candidates in several hotly contested races in the Nov. 4 general election.

Kemp, a Republican, has adamantly denied those claims, saying he began the investigation only after local elections officials raised concerns over about 100 individual forms they received from the group. Investigators said they have no evidence of conspiracy by the group’s leaders, but that the forged applications seem to be the individual work of canvassers paid by the group during its registration drive.

Still, GOP leaders took a partisan tack on Thursday with a "Stand with Brian" informational drive.

Local officials, meanwhile, were still digging through piles of voter applications, including thousands in Muscogee and Fulton counties — the counties with the most pending voter applications

Fulton County alone is still trying to reach more than 7,700 people to ask for more information related to their applications, with 209 letters mailed just on Thursday. Processing of so-called “pending” voters can be held up for a number of reasons, including the need to verify Social Security numbers, citizenship status and home addresses, or to reconcile a clash with information kept by the state’s Department of Driver Services.

Fulton elections director Richard Barron expected the number to drop significantly as his office receives more letters back with information. Still, “it is a time-consuming process,” Barron said, since each voter has to be researched individually.

Muscogee elections director Nancy Boren said her office is still processing 1,500 of the 11,000 applications submitted by the New Georgia Project. The office is also seeking more information from an additional 2,000 pending voters.

The state investigation could take months to complete as the office digs through more applications and the project’s records. This week, investigators added Dougherty and Douglas counties to a list where suspicious forms have been reported. The other counties involved in the investigation are Bartow, Butts, Cobb, Coweta, DeKalb, Effingham, Gwinnett, Henry, Muscogee, Paulding, Tattnall, Terrell and Toombs.