By GLORIA MARINA and GENE MILLER

To a fragment of Miami's Cuban community, Humberto Lopez Jr. is a hero and a martyr.

To others in Miami, he is a coward, a fanatic, and a fool.

To a band of terrorists, Humberto Lopez Jr. is an excuse to plant more bombs in Miami and frighten people.

To the U.S. government, he is a convicted felon who ran away. His future appears assured: He will be in prison a long time.

HIS APPREHENSION was not among the most significant accomplishments of the Dade County

Public Safety Department, the Miami Police Department, and the FBI, all of whom are trying to catch bombers these days.

In the past 24 months and 25 days, 52 bombs have exploded in Dade County. Police have solved only one bombing case and arrested two bombers - two who had the misfortune to blow themselves up.

Lopez is one of them. He has a plastic left eye and wears his wedding ring on his right hand. That's because he lost three fingers of his left hand when he got careless with a mousetrap. The mousetrap detonated his bomb in a workshop.

Lopez considers himself a Cuban. patriot. By tape recordings, he once exhorted his fellow Cuban exiles "to sink ships, bomb factories, blow up embassies and invade our country any way we can."

Lopez, now 33, is a mustachioed, not unhandsome man with a nervous twitch that jerks his shoulders and a fondness for war movies, karate movies, and cowboy movies.

He is a homebody who used to lift weights, and until he got caught, he washed his car every Sunday, mowed the lawn, and played chess with his father.

His father was one of the Miami Cubans who went to Washington for J. Edgar Hoover's funeral with Watergate burglar Bernard Barker. They were there to harass the anti-Hoover pickets.

HUMBERTO JR. was born in Havana on Dec. 7, 1941, fatefully perhaps, on the date that Japan attacked Pearl Harbor by bomb and stealth. He was an only child.

His father, Humberto Sr., an articulate, forceful, and highly political anti-Communist union official, divorced his mother, and was given custody of his son. He put his boy into Havana's prestigious La Salle school.

Father and son left Cuba for Miami when Carlos Prio fell from power, and at age 15 Humberto Jr. attended Miami Jackson High School in 1956.

They returned to Cuba in 1959 when Fulgencio Batista fled for Santo Domingo, and Humberto Jr. studied political science and jurisprudence for about a year and a half at the University of Havana.

IN 1960 Fidel Castro's militia decided it wanted to make young Lopez a militiaman. Humberto didn't want to go. The G-2 imprisoned him briefly. His father persuaded the Brazilian ambassador to intercede, and father and son soon were living in Venezuela.

Father Lopez became an editor and radio announcer for "The Anti-Communist Voice of America." Junior became a junior announcer.

They returned to Miami in 1962 and Lopez enlisted in the U.S. Army. After the Cuban missile crisis, the Army paid a lot of attention to its Cuban-born soldiers. Lopez learned about bazookas, dynamite and commando raids at Ft. Knox and Ft. Jackson.

He was a good soldier, said his friend Manolo Guerra. He kept his shoes shined, his uniform pressed, and when they hit town on pass, he stayed out of bars. He didn't drink. He didn't go dancing either. He read a lot - both in English and Spanish.

THE ARMY psyched him up, Guerra feels. "We really felt we were going to go and fight in Cuba."

When discharged honorably, the CIA recruited Lopez. This is according to his friend, Genaro Perez, who says he trained with him in Costa Rica and Nicaragua for $175 a month, plus room and board.

The CIA prefers not to talk about its former employees. "It is not in the great and sterling tradition of intelligence agencies," said Angus Thuermer from Washington.

What Lopez did for the CIA, if anything, remains unsaid by his friends.

IN 1966 Lopez moved to California, courted a divorced woman with a son, married her in Los Angeles on June 27, 1968, and worked in a machine shop for Northrop Corp., an aircraft manufacturer.

For his wife, Matilde, he made a sofa, built a bookcase, and rode around the block on a bicycle with his stepson. Sometimes he and his wife would wear look-alike clothing. Lopez also took flying lessons in California, but he quit before he got a license.

In 1972 he returned to Miami and took lessons for a real estate license. But he quit that too. He got a job as a field manager for the U-Haul Co. It paid $700 a month.

In the living room corner of a modest home at 460 W. 42nd Pl. in Hialeah, Lopez installed the Cuban flag and a plaster bust of Jose Marti, the historic Cuban patriot.

He wore a chain and gold medal of Marti around his neck.

HE GOT HIS name in the newspapers in the summer of 1973 when a fire broke out in his garage. Somebody called the fire department.

Firemen found more than a fire. They found four hand grenades, a 60mm mortar, two M14 rifles, a silencer-equipped .45 caliber submachinegun, a 50mm cannon, a 60mm cannon, and four cases of ammunition.

Lopez, it developed, had belonged to the Golden Falcons, a skydiving club composed of ex-paratroopers connected to the exile Committee For Liberation.

"At first he said he wasn't home when the fire began," said Metro bomb squad detective Newton Porter. "Then he said he was fueling his lawnmower and it backfired."

DETECTIVE Porter, suspecting that Lopez was trying to destroy something when the fire started, made his speech against super patriots. He figured - correctly -that Lopez was behind some of the bombings.

"Castro is in Cuba, not Miami. I don't see him quaking in his boots and biting his cigar when a bomb goes off in Miami. Some innocent people are going to get killed one of these days."

Lopez got off easily that time. Dade Circuit Court Judge Ralph Furgeson convicted him of possession of hand grenades, but withheld adjudication.

It was 12:30 p.m. March 20, 1974 that Lopez and a fellow bomber, Luis Crespo, blew themselves up. Crespo also survived. He lost both hands. He is now in prison.

THEY WERE in a garage workshop of a friend's house at 2344 SW 16th St. They had with them C-4 plastic explosive, a small radio battery, and a mousetrap.

They also had a hollowed-out history book about the Battle of New Orleans. The bomb was supposed to fit inside and make a nice package, suitable for mailing.

"I let them use my workshop because they were good friends of the family," said Alfredo Sayus Jr., owner of the house.

He was in bed when the explosion rocked the house. He bolted for the workshop. The door was locked. He kicked it in and found the two men unconscious and bleeding.

THIS DIDN'T prevent their sympathizers from claiming that Crespo had grabbed his shattered right arm in the instant after the explosion, and had supposedly cried, "Viva Cuba Libre!"

"My son is a patriot. He was working for the freedom of Cuba," Lopez Sr. proclaimed the next day.

According to the FBI and Metro investigators, the two men had built the bomb for a Miami Cuban radio announcer whose views they disputed.

Days later Lopez allegedly was scrawling a "combat" message on a blackboard from his hospital room: "We call upon you to close ranks and to continue fighting until we cross the last foxhole."

Abdala, a militant anti-Castro youth group, among others, took it seriously. It reportedly raised $12,158.61.

THE STATE tried Lopez and Crespo for unlawful possession of explosives in September, 1974 before Circuit Judge Arden Siegendorf.

"Look at their hands," said Assistant State Attorney James Woodard. "If this isn't vivid proof of possession, then what is?

"What would have happened to the person who would have opened that book? What would have happened if it had gone off in the post office?" he asked.

Defense attorney Melvin Greenspahn disagreed. "The basic question of possession could be resolved by fingerprints - but there are none," he argued.

The jury was unimpressed. It convicted both men.

MIAMI MAYOR Maurice Ferre, a man with strong Latin political affiliations, later got into the act. On his private stationery, he told the court: "I wish to enter on the record that I know the two defendants and believe them to be men of good character standing."

Afterward, Ferre decided his testimonial had been based on "bad information" and that his action had been "stupid" and "foolish." He rescinded his testimonial.

Federal prosecutors, meanwhile, had also taken a shot at Lopez for possession of unregistered artillery, automatic rifles and machineguns found after the fire.

The seven-foot barrel was a cannon, Assistant U.S. Attorney William Northcutt insisted. A jury believed him.

LOPEZ didn't testify. He didn't say anything publicly until he had jumped bond and fled before he was to be sentenced by U.S. District Court Judge Joe Eaton.

He spoke from hiding by a tape recording given to The Miami News and radio station WFAB. He went on for five minutes:

"The FLNC (National Cuban Liberation Front) continues its march onward and proclaims that only with blood, sweat and sacrifice will we reach victory . . .

"I don't ever intend to serve even a day in the jail of those who had feigned themselves as our allies and have instead done nothing but betray us and torn against us . . . I don't belong to the race of men who bend their knees . . .

"HONOR made it necessary for an explosion to leave us maimed for a lifetime, wounds of duty and of glory. We shall stand in readiness always a s long as the homeland's shame and honor demand it."

Lopez lived as a fugitive for a year.

He was arrested in Santo Domingo in late September. His father said that a Santo Domingo general had "betrayed" his son.

"My son and the general had become friends and the general knew who he was. My son was told the general was trying to square things so he could legally reside in Santo Domingo."

Instead, said the father, the general brought a police captain and a police major to his office and the major "put a gun to my son's head, cocked it, and told him he was arrested and that unless he came with them to the police headquarters he would blow his brains out."

"THEN THEY threw him, totally naked in a solitary cell. For three days they gave him neither water nor food."

Lopez arrived under guard at Miami International on Oct. 4. His father said an FBI man was with him. An FBI spokesman said there wasn't "to my knowledge. There might have been one aboard as a passenger."

Apparently Lopez arrived in good spirits. "He told me, 'Father, this is paradise. I have just come from hell,' " Lopez Sr. said.

Since his return, three bombs have exploded.

On Oct. 6 a blast blew out the windows of the Dominican consulate at 1038 Brickell Ave.

On Oct. 10 a blast knocked out 45 windows of a church school in Fort Lauderdale. This was 300 yards from the Brow and Jail, where Lopez boas in custody.

Fort Lauderdale police didn't recognize it as a bomb blast at first. They thought the windows broke from a sonic boom. They speculated that vandals had shot them out with B-B guns.

Three days later they discovered a hole in the ground and a clock gear.

The third bomb occurred in a luggage locker at Miami International Airport Oct. 17.

A fourth bomb containing eight pounds of dynamite was defused Oct. 20 near the Dominicana Airlines office at 1444 Biscayne Blvd. It was also near a sidewalk bus stop and the entrance to the Social Security office.

Lopez, of course, is innocent of these. He is in jail. He may well be there a long time.

His federal trial for jumping bail is set for Nov. 3. He could get 25 years for that.

U.S. District Court Judge Eaton will also sentence Lopez for the arms possession conviction. He could get up to 50 years for that

In the state court, Lopez also faces up to 30 years for possession of the arms discovered in his garage fire and the workshop explosion.

His lawyer, Gino Negretti, filed a motion the other day, claiming his client is a "political fanatic" and "mentally incompetent." He asked for psychiatric examination.

A U.S. marshal had Lopez in the backseat of a car one day last week. "Do you think they are making a martyr out of you?" he asked.

Humberto Lopez Jr., he said, "hemmed and hawed, nodded, and looked at the floor and smiled."