The top Miami-Dade County criminal prosecutor assigned the task of convicting the alleged killer of Jimmy Ryce is resigning after being snared in an office sex scandal, accused by a secretary he supervised of fondling her breasts at work.

In a county rampant with scandals, Chief Assistant State Attorney Michael Band appears to be its latest victim. The prosecutor’s final case for the state will be the murder trial of Juan Carlos Chavez, 30, accused of killing Jimmy Ryce.

Band’s announced resignation came on the heals of an investigation into his relationship with Shelly Rossbach, a 20-year legal secretary/trial coordinator in his office.

The accusations against Band by Rossbach emerged during an unrelated investigation into why Rossbach and other secretaries at the Miami-Dade State Attoney’s Office were having hours-long, sexy telephone calls from their cubicles with admitted hit-man Jorge Ayala, a frequent informant known to the secretaries.

They were also accepting hundreds of dollars from Ayala, who is serving time in a Miami federal prison, the investigation revealed.

During the investigation, conducted by an outside prosecutor, Rossbach said she had been “historically sexually harrassed by Band,” her boss in the unit.

She said on December 1997, Band accosted her in his office and fondled her breasts, a potential battery. She rejected him. From that day on, Band would not speak to her. She said he set out “to humilate, discredit and terminate her.”

The sex scandal has rocked the office, headed by Kathy Fernandez Rundle, at a time when it has launched several successful investigations into public corruption.

Two other veteran secretaries were also terminated on Friday for allegedly having improper relationships with Ayala.

The silver-haired Band, who handled the Gianni Versace murder investigation and won a conviction in the murder of a German tourist, will end his 18-year career after the Ryce trial, said Don Nelson, the office’s executive director.

The trial is set to begin in September in Orlando.

Band, one of three supervisors in the major crimes unit, was viewed as the office’s top prosecutor and usually handed the high-profile cases.

When approached about Rossbach’s accusation, Band refused to take a polygraph test, the report says.

Instead, he rendered a letter of resignation this month. Band cited financial reasons.

“After much reflection and soul searching, I have concluded that this is the appropriate time for me to tender my resignation,” he wrote.

Band, who is married, could not be reached for comment.

“As soon as we knew about the allegations against him, we informed him,” Nelson said. “After that, Band resigned.”

Rossbach has decided not to file criminal charges against Band, and neither will the State Attorney’s Office, Nelson said.

Nelson said Band’s pending departure should not hurt the Ryce case.

“We are thrilled that he is finishing up with that prosecution,” Nelson said. Don and Claudine Ryce, Jimmy’s parents, were also consulted about Band’s resignation. They asked that he stay on.

The legal secretaries fired on Friday for allegedly fraternizing with Ayala are Raquel Navarro and Barbara Abad. A third secretary, Olga Cabrera, was terminated on an unrelated charge of forging signatures on legal papers. Rossenbach was not fired as a result of the telephone-call investigation.

From Miami’s federal prison, Ayala persuaded the women to transfer calls to outside lines, or have long conversations with him ” about their personal lives,” according to the report.

Some of the secretaries were then receiving money orders for as much as $150 from Ayala, the investigation shows.

“They clearly crossed the line here,” Rundle Fernandez said of the secretaries, who even fought over Ayala.