MEXICO CITY (AP) _ Rafael Caro Quintero, the key suspect in the kidnap-slaying of a U.S. narcotics agent, has been ordered to stand trial on drug charges.

Ernesto Fonseca, reputed to be Mexico's leading drug dealer and head of the trafficking combine known as La Familia, was scheduled to be arraigned today before a federal magistrate on multiple drug charges.

A brief the Attorney General's Office filed with the court Thursday night listed the principal charge against Fonseca as ''crimes against the health of the nation.''In Mexico, this can include a variety of narcotics charges, including trafficking.

But the brief indicated the case may also be linked later to the kidnap- murder of the American narcotics agent, Enrique Camarena Salazar, and a Mexican pilot who worked for Camarena Salazar, Alfredo Zavala Avelar. First Criminal Court Judge Pedro Elias Soto Lara scheduled the arraignment hearing for Fonseca and 23 bodyguards and accomplices. All were arrested after a brief shootout Tuesday in the Pacific resort town of Puerto Vallarta.

More than 150 special police officers surrounded Fonseca's luxurious villa in Puerto Vallarta for the arrest. Police were said to have found an arsenal of high-powered weapons.

Also known as ''Don Neto,'' the 60-year-old Fonseca, a reputed drug dealer for more than 40 years, was the second Mexican drug baron brought to trial this week in the biggest government crackdown against the country's narcotics trade.

Caro Quintero, arrested April 4 in Costa Rica, was ordered Thursday by Judge Soto Lara to stand trial for ''crimes against health,'' criminal conspiracy and weapons smuggling.

He is also wanted in Guadalajara in connection with the kidnap-slaying of Camarena Salazar and Zavala Avelar.

According to U.S. officials, La Familia - or The Family - is based in Guadalajara and controls tons of narcotics that pass through Mexico from South America en route to the United States.

The officials estimate that nearly 30 percent of marijuana and cocaine and 38 percent of the heroin used in the United States comes from Mexico.

In Washington, deputy State Department spokesman Edward Djerejian noted the two arrests, saying: ''This means that two of the most prominent reputed kingpins among narcotics traffickers in Mexico have been captured. This is a very positive indication of the Mexican government's commitment to combat the traffickers.''

Caro Quintero, 29, was arrested with six accomplices in San Jose, Costa Rica last week. Mexican law enforcement officer say he was a top enforcer and accomplice of La Familia.

A Guatemalan police report said six more Fonseca accomplices were arrested in Guatemala on Wednesday, including a Japanese identified as Isao Sasaki.

The report Thursday evening said Sasaki arrived in Guadalajara in 1976 and worked as a cook in a Japanese restaurant until 1983 when he went to work for Fonseca.

The Attorney General's Office has said Caro Quintero is the prime suspect in the kidnapping and slaying of Camarena Salazar, 37, and his pilot.

Both were kidnapped in Guadalajara Feb. 7. Their badly beaten bodies were found, wrapped in plastic bags, March 5 on a ranch 60 miles southeast of that city, the capital of Jalisco state.

Six Jalisco state policemen and a former officer are being tried in connection with the kidnapping.

Also arrested for trial on bribery charges was Armando Pavon Reyes, commander of the Federal Judicial Police in Guadalajara, and the man initially in charge of investigating the two killings.

In a confession he repudiated later, claiming it was extracted under police torture, Caro Quintero said he paid Pavon Reyes $300,000 to allow him to flee Guadalajara Feb. 9 in his private jet, despite requests from DEA officials to detain him.

At the time, witnesses said Caro Quintero gave Pavon Reyes a farewell embrace at Guadalajara airport before boarding the plane. He was subsequently fired.