FORT WORTH (CBSDFW.COM) – Four women are facing felony charges, accused of being part of what Attorney General Ken Paxton’s office called an organized voter fraud ring in Fort Worth.

The voter fraud charges involve mail-in ballots sent in ahead of the 2016 primary election in Texas. Paxton’s office said the case targeted elderly voters on the north side of Fort Worth.

While calling it an organized ring, the Texas Attorney General’s Office could not say if investigation was ongoing or if additional indictments could be expected.

A grand jury indicted Leticia Sanchez, Leticia Sanchez Tepichin, Maria Solis and Laura Parra on Wednesday.

Paxton’s office said the women harvested votes, by filling out applications for mail-in ballots, with forged signatures. Then they would either “assist” the voter with filling out the ballot, or fill it out themselves, and use deception to get the voter to sign the envelope the ballot would be sent back in.

Political consultant Aaron Harris said Friday the case stemmed out of information he provided to investigators back in 2016.

“The harvesters sit around and fill these out by the hundreds, often by the thousands,” he said Friday.

Harris publicly presented documents that year of signatures that didn’t match on applications and envelopes.

In October, Governor Greg Abbott posted on Twitter about a voter fraud case under investigation in Tarrant County.

Harris said he’s documented a number of additional people involved in the ring, but recognized the cases can be difficult to prosecute.

“Just because they may have been indicted on one or two, or 16 counts, doesn’t mean they don’t have 200 counts but those are the only 16 that can be proven,” he said.

Tarrant County elections administrator Heider Garcia said Friday his office had cooperated with state investigators. He had not reviewed the indictments but said he expected to reach out to the attorney general’s office to see if anything was identified in election procedures that needed to be corrected.

The indictments show several of the ballots in question were for Democratic candidates.

Tarrant County Democratic Party Chairwoman Deborah Peoples said she had met Leticia Sanchez in the past.

She said she was not aware of specific details of the case though, and she questioned the timing of the indictments, less than four weeks ahead of the November midterm elections.