A federal grand jury that indicted the former Key West Public Works superintendent and three of his family members on charges that they operated a tax fraud scheme from the Monroe County jail netted four more people Tuesday.

Former inmate Shawn Patrick Clarke and three of his family members were charged with one count each of conspiracy to defraud the IRS and 24 counts each of making false statements to the IRS, according to a 25-count indictment unsealed Tuesday.

Also charged were his mother, 63-year-old Delray Beach resident Sally Frost; his brother, William Clarke, 40, also of Delray Beach; and his sister, Deanna Heder, 39, of Fort Myers.

All face a maximum of 130 years in prison if convicted on all counts.

Shawn Clarke, 36, was in Monroe County jail for violating parole and currently is serving a five-year sentence for battery at Zephyrhills Correctional Institution.

Frost, William Clarke and Heder all made initial appearances in federal court in Miami Tuesday afternoon. Shawn Clarke is expected to be extradited to Miami later this month, reports say.

Investigators allege Shawn Clarke helped spearhead a scheme with as many as 50 other inmates between 2004 and 2007 that bilked taxpayers out of hundreds of thousands of dollars. Inmates allegedly submitted false tax returns in the name of fellow inmates, former inmates and relatives in which they claimed they had been employed and paid withholding taxes during the years in question.

Those involved in the alleged scheme applied for tax withholdings from recently closed or bankrupt businesses elsewhere in Florida, according to the Monroe County Sheriff's Office. Investigators allege family members who were not in jail would cash the checks and funnel the money back to those behind bars.

The grand jury on Friday indicted former Key West Public Works Superintendent Gilbert Suarez, 47, and his brother, 49-year-old Danilo Suarez, another alleged mastermind in the jail scheme, according to prosecutors.

Danilo Suarez was serving time in the Monroe County Detention Center on Stock Island from 2004 to 2006 on cocaine charges, according to the Department of Justice. Also indicted were Danilo Suarez's daughter, Sandra Suarez, and sister, Belkis Mendez, both arrested in Key West on Friday.

Danilo Suarez is currently serving prison time in Williamsburg, S.C., on a cocaine-related conviction. Gilbert Suarez made his first appearance in court Monday and was released from custody with a notice to appear in court again, according to the Florida Department of Corrections.

For years, former Sheriff Rick Roth and his investigators built a case against Shawn Clarke and Danilo Suarez, and criticized the IRS for not doing anything. Current Sheriff Bob Peryam said he is working with the IRS and hopes more arrests are coming.

"We're heading in the right direction," Peryam said. "I'm glad to see this is still an ongoing investigation. I haven't heard anything about more arrests, but I hope they don't stop here."

alinhardt@keysnews.com