PROVIDENCE — The ringleader of a large-scale drug-peddling operation, whose arrest caused a minor sensation because the police said she and at least five of her alleged conspirators were collecting welfare from the state, has pleaded no contest to four charges.

Joanna “Rosa” Gonzalez, a 28-year-old mother of three, and 28 other people were arrested and charged in connection with an investigation that the police dubbed Operation Rosa. The police said the crack-selling ring was an unusually businesslike family enterprise that included Gonzalez’s mother, sister, aunt and live-in boyfriend and used young children as lookouts and drug runners.

In a plea bargain with state prosecutors, Gonzalez was promised that the state would seek a maximum sentence of 15 years’ imprisonment and that the sentence would incorporate her violation of the terms of a suspended sentence on a previous conviction of assault with a dangerous weapon, Special Assistant Attorney General James F. Dube said yesterday. She is scheduled to be sentenced next month.

Attorney General Patrick C. Lynch announced that Gonzalez, of 49 Anchor St.; her mother, Evelyn “Diamond” Caraballo, 46, of 102 Berkshire St.; her sister, Evelyn Gonzalez, 26, of 135 Terrace Ave., Cranston; and her boyfriend, Michael “Ice” Taylor, 22, also of 49 Anchor St., have pleaded no contest to drug charges in Superior Court. Except for Joanna Gonzalez, they also have been sentenced.

Also yesterday, two lesser players in the operation, Xiomara Guitard, 24, and Tania Rivera, 28, pleaded no contest to drug charges and were sentenced.

Joanna Gonzalez and at least two of her alleged conspirators drove luxury cars registered in their own names even as they collected welfare checks, the police said when the ring was broken up in July after a wiretapping investigation mounted by the police and the U.S. Drug Enforcement Administration.

The police seized six automobiles and two motorcycles and are seeking to have them declared forfeit as the proceeds of illicit drug sales, according to Lt. Thomas Verdi, commander of the Providence police Narcotics and Organized Crime Bureau.

An investigation of possible state and federal benefits fraud is being conducted by the police, the state Department of Human Services and the U.S. Social Security Administration.

In the plea-bargaining with the six defendants who have entered pleas in Operation Rosa, Dube said the attorney general has promised not to seek additional prison time if they are found to have obtained government benefits illegally. The attorney general may, however, pursue restitution, forfeiture or other financial penalties, he said.

Superior Court Judge Susan E. McGuirl, who has been handling the disposition of the Operation Rosa cases, has said in each case, however, that the court won’t guarantee that the defendants will be spared additional prison time if they have committed benefits fraud.

“A drug-dealing operation of this magnitude — which provided its ringleader and major operators with the means to lead lavish lifestyles — put an enormous amount of illegal drugs on the streets of our capital city,” Lynch said in a statement.

“Through solid investigative work, cooperation and collaboration, the family at the heart of this enterprise, plus many employed in various aspects of this large illegal ring, are off the streets and out of business.”

Police Chief Dean M. Esserman commended Verdi, Detective Peter Conley, the lead investigator, and the others who worked on the case for having carried off a difficult and labor-intensive project.

Joanna Gonzalez, who gave birth to her third child while incarcerated at the Adult Correctional Institutions following her arrest, pleaded no contest on Sept. 12 to racketeering, racketeering conspiracy, possession of one ounce to one kilogram of cocaine and possession of cocaine with intent to deliver.

Caraballo pleaded no contest to racketeering and racketeering conspiracy. Judge McGuirl imposed a sentence of 10 years, with six months to serve, one year of home confinement, and 8½ years suspended with probation, on each count. The sentences will run concurrently.

Evelyn Gonzalez, pleaded no contest to racketeering, racketeering conspiracy, delivery of cocaine, and conspiracy to deliver cocaine. She was sentenced to 15 years, with 6 years to serve and 9 years suspended with probation, on the cocaine delivery count with lesser concurrent sentences on the other three counts.

Taylor pleaded no contest to six counts and was sentenced to 15 years, with 6 years to serve and 9 years suspended with probation, with lesser concurrent sentences on other five counts. Three of the counts stemmed from Operation Rosa and three were unrelated drug charges.

gsmith@projo.com