Three more people arrested in a sweep by federal drug authorities in February have pleaded guilty in federal court in San Francisco to conspiring to distribute methamphetamine and heroin.

U.S. Attorney Joseph Russoniello said Cornelio Mata Espinoza, Anthony Johnston and Josefina Rodriguez pleaded guilty to the conspiracy charge before U.S. District Judge Charles Breyer on Wednesday.

Johnston also pleaded guilty to an additional count of possession of a gun by a convicted felon, Russoniello said.

Another defendant, Franco Perez, 38, of Redwood City, pleaded guilty to the conspiracy charge before Breyer last week.

The four defendants are among nine people arrested in the Bay Area by law enforcement agents on Feb. 4 in an investigation that authorities called Operation Smack Down. They were indicted on Jan. 29 on a variety of drug and money laundering charges.

Rodriguez will be sentenced by Breyer on Dec. 9, Espinoza and Perez on Jan. 13, and Johnston on Jan. 20.

In plea bargains, prosecution and defense lawyers agreed on a sentence of between seven years and three months and nine years in prison for Rodriguez; between 16 and 27 years for Espinoza; and between 14 years and 21 years and 10 months for Johnston.

Perez agreed to serve at least 17 years and six months in prison, Russoniello said.

If the judge gives a defendant a sentence above or below the recommended range, either the prosecution or defense can set aside the plea and have a trial for that defendant on all charges in the indictment.

Russoniello said Rodriguez, Espinosa and Johnston admitted during their pleas to selling methamphetamine and heroin in the Bay Area. Rodriguez also admitted that $353,877 seized from duffel bags in her car last year were drug profits.

Perez admitted during his plea last week that he helped coordinate the smuggling of more than 13 pounds of methamphetamine from Mexico into the United States inside the transmission of a pickup truck in November, Russoniello said.

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