INDIANAPOLIS (AP) — Two inmates housed at different Indiana prisons used cellphones smuggled in by guards to run a drug ring that distributed methamphetamine and heroin, according to a federal indictment that charges 40 people in connection with the scheme.

Prosecutors, in the indictment unsealed Wednesday, allege that the purported ringleader, Oscar Perez, and an inmate at another prison, Justin Addler, even used the smuggled phones to hold conference calls with a third man to discuss "pooling their financial resources" to get a discount on heroin.

At least 17 people appeared in court Wednesday in Indianapolis after about 300 FBI agents fanned out across the state and made arrests. A judge ordered them to remain in custody. Only one prison guard was among those charged, though the indictment alleges several were involved. Prosecutors declined to say if more charges were expected.

FBI Special Agent Wendy Osborne said two of the 40 people indicted — 39-year-old John Smith and 35-year-old Jermaine Coleman — remained at large Thursday morning. She didn't know the men's hometowns and said she couldn't comment further about the case.

Few details about the defendants were included in the court documents, although prison records show Perez is serving time for murder and attempted murder at Westville Correctional Facility in northern Indiana, while Addler is housed at central Indiana's Pendleton Correctional Facility on convictions including drug dealing.

The indictment details a series of alleged phone calls the two men placed to people outside the prisons, including calls to arrange the purchase of "large amounts" of heroin from a source in Chicago. They also instructed people how and where the drugs should be sold, prosecutors allege.

"Once acquired, the heroin was brought from Illinois to Indiana by the use of couriers where it was, in turn, distributed on the streets to various places" in central and southern Indiana, the indictment states.

Meth was acquired from sources in California, while other drugs, including PCP, were also involved, according to the indictment.

In at least one call in May 2012, Addler stayed on the phone with a woman "throughout the duration" of a drug deal as she sold about 20 grams of heroin at a truck stop in Crawfordsville, Ind., for $2,500, according to the indictment.

Tim Horty, a spokesman for U.S. Attorney Joe Hogsett, declined to discuss the indictment, including whether additional inmates or prison guards might be charged. Doug Garrison, a spokesman for the Indiana Department of Correction, also declined to comment.

The lone corrections officer facing charges, Jon Dobbins, worked at another prison, the Wabash Valley Correctional Facility in southwestern Indiana. The indictment alleges he was found "in possession" of nearly 21 grams of a substance containing meth, and had a cellphone that he intended to "clandestinely bring" into the prison and leave with an inmate.

Dobbins didn't have a listed phone number in Indiana, according to phone records. Horty confirmed that Dobbins was the only correctional officer named in the indictment, but he declined further comment.

The Indiana Department of Correction issued a statement saying it has been cooperating with the FBI since the investigation began and that that department uncovered the evidence that led to Dobbins.

"The actions of the small number of any IDOC correctional employees who may have facilitated these illegal activities brings dishonor to them and tarnishes the good name and professionalism of the vast majority of IDOC employees," the department's statement said.