PERTH AMBOY, N.J. (AP) — Three political campaign workers have been indicted on charges stemming from a scheme where authorities say one offered $20 supermarket gift cards to voters in return for letting her complete their mail-in ballots.

The Middlesex County Prosecutor's Office announced Thursday that a county grand jury indicted Ana Camilo, 62, of Perth Amboy, on two counts of bribery, unlawful possession of a ballot, attempt to cast an illegal ballot and election law violation.

Camilo was arrested last October after authorities said she met with and tried to bribe an undercover detective posing as a Perth Amboy voter. Authorities have said Camilo was working for a Perth Amboy city council candidate but have not disclosed the person's name.

Two other Perth Amboy residents — Annet Sanchez, 52, and Maria Peralta, 60 — were each indicted on a charge of retaliation against a witness. They allegedly harassed the person who provided information concerning Camilo’s involvement in the voter fraud scheme, according to prosecutors.

It wasn't clear Thursday if any of the campaign workers had retained attorneys. Authorities said the the three have nothing to do with the county or city election offices or operations.