Jamiel (Jimmy) Chagra, a convicted drug dealer, and contract killer Charles Harrelson were indicted yesterday for murder and conspiracy in the 1979 assassination of U.S. District Court Judge John H. Wood Jr. in San Antonio. Three other persons were indicted in connection with the slaying.

The indictments were announced here by FBI Director William H. Webster, who said the three-year investigation into the Wood killing was one of the most extensive and expensive in FBI history, costing more than $4.7 million, involving more than 70 FBI agents at times and including 214,000 investigative entries into the FBI computer.

"We started from nothing and built a case up," Webster said, adding that there were no eyewitnesses to the shooting and "virtually no forensic evidence at the scene."

Webster said the massive effort by the FBI and other law enforcement agencies was intended to "send a message" to criminals who believe they can intimidate the criminal justice system.

"It is a strong signal, a definite signal that should be apparent to all who care to listen," he said. He said the large amounts of money changing hands among drug traffickers have "generated a kind of arrogance that allows them to take on institutions.

"His murder was a direct attack on the system of criminal justice and the rule of law that are such integral parts of our American way of life," Webster said.

Wood was gunned down as he walked from his apartment to his car the morning of May 29, 1979.

Wood, nicknamed "Maximum John" because of stiff sentences he handed down against drug dealers, had been scheduled to preside over Jimmy Chagra's trial on charges that he smuggled cocaine from Colombia to the United States from 1976 to 1978.

Yesteray's indictments charge that Jimmy Chagra hired Harrelson for $250,000 to kill Wood.

Chagra's wife, Elizabeth N. Chagra, and his brother, Joseph Chagra, also were charged with conspiracy to murder. All four, as well as Harrelson's wife, Jo Ann Starr Harrelson, were charged with conspiracy to obstruct justice.

"It was a part of the conspiracy that, fearing Judge Wood would impose substantial prison sentences on Jimmy Chagra in the event he was convicted in the narcotics case, Joseph Chagra and Elizabeth Chagra counseled and encouraged and agreed with Jimmy Chagra to have and cause Judge Wood to be killed," the indictment said.

Wood was shot once in the head with a high-powered rifle that prosecutors say they believe was purchased by Mrs. Harrelson several days before the killing.

Jimmy Chagra, who lists his occupation as "gambler," is already in the federal penitentiary in Marion, Ill., serving a 30-year sentence for a conviction for conducting a "continuing criminal enterprise" involving cocaine smuggling. Harrelson is in a Huntsville, Tex., prison on drug and weapons convictions. He has been convicted of killing for hire. The other three were arrested early yesterday, before the indictments were released. Bond for Joseph Chagra was set at $2.1 million.

Jimmy and Joseph Chagra also were charged with conspiracy to possess marijuana with intent to distribute and possession of cocaine with intent to distribute.

A separate indictment charges the three Chagras and Mrs. Chagra's father, Leon Nichols, with federal income tax evasion. The indictment said that an attempt had been made to conceal Jimmy Chagra's assets and convert them to cash in order to help him escape from federal prison.

Webster said that, in addition to local law enforcement agencies, the FBI was aided in the investigation by Canada, Mexico and Colombia.