"I'm going to be a great man and save you from this," Mehmet Ali Agca, the Turk accused of shooting Pope John Paul II used to promise his impoverished family in the dirt-poor Gazi district of this provincial city.

Gaunt, tight-lipped, a bookish loner with no known childhood friends, according to family members and their acquaintances, Agca seemed to have the drive, intelligence and family support fo fulfill his vow of breaking away from the life of deprivation in which he and his family were immersed.

Instead, he is under tight guard in Rome's police headquarters, accused of attempting to assassinate one of the world's most respected men, and wanted in Turkey for killing one of his own country's prominent men.

Some of Europe's most formidable police forces are hunting for information to reconstruct Agca's life, travel and contacts between Feb. 1, 1979, when -- as he has confessed -- he shot liberal Turkish editor Abdi Ipekci in front of his Istanbul house, and May 13 of this year, when the pontiff was shot in front of St. Peter's.

But for deeper clues to the mystery of this violent and secretive man of 23, one must come to Malatya, a city of 184,000 on the edge of the brooding plateau of central Anatolia. In this obscure place can be found a volatile mix of social disorder, cultural upheaval and political absolutism that sometimes spawns the terrorism of these times.

Named for a gradfather who was killed during military maneuvers at the time of the Turkish war of independence in the 1920's, Agca barely knew his own father, Ahmet, who died in 1965 while working at a coal mining city on the Black Sea.

According to Agca's mother, Muzeyyen, she moved her family of small children the same year from their ancestral hamlet of Hekimhan to Malatya. It was a distance of 45 miles that still takes 2 l/2 hours by bus and it plunged a rural family into urban life.

They moved into a small three-room apartment on the ground floor of a modest building in the Gazi section, near the central police headquarters, but cut off from the rest of Malatya by the tracks of the main rail line from Ankara. Here Mrs. Agca subsisted on widow's benefits and raised her children: Mehme Ali, daughter Fatm and youngest son Adnan.

Mehmet Ali, whose current photographs portray a staring hostility to the world, was quiet, sensitive and took refuge in school from the teeming ghetto life around him, getting excellent grades. "He knew our situation, our poverty. He was a thinking person," said his mother during an interview in the one-room flat where she now lives, a few blocks from her old home.

Agca began working at odd jobs at 8, earning about two cents a piece hawking glasses of safe drinking water at the nearby train station. As he matured, he took construction jobs that paid a little better, or worked as a bus boy in the city's myraid coffee shops.

He was clever and resourceful, said Mrs. Agca. "He was able to squeeze his bread out of a stone." In his spare time he retired to his books, "going to a corner all by himself," she said as she knelt on a small mat on the floor of her home.

She could not say what books he read, for she is illiterate. "I am an old peasant woman. I have no education." She thinks he read "textbooks. I don't know of any others."

Her son did not seem deeply affected by the Moslem faith he kept, she recalled, although he went to several weekend study sessions at the mosque. He did fast for several days at Ramadan, although not the prescribed 40.

Mrs. Agca's face, at 50, is gaunt and framed with graying hair, tucked under the filmy shawl that many women here wear over their heads and pull across their mouths.

In the early 1970s, when Agca was entering the turmoil of adolescence, Turkey was also entering a period of severe political strain. The military intervention of 1971 restored order but the country was lurching into chaos with its parliamentary system faltering and polarization between left and right in the streets.

The Arab oil embargo of 1973 and the sudden price increases that followed brought economic turmoil as well. Turkey, which produces about 10 percent of its own oil, was in trouble.

Meanwhile, Malatya had new difficulties of its own. In 1971, the U.S. government pressured Turkey to outlaw its profitable opium industry. As a veteran municipal leader said bitterly today, "They couldn't solve their own problem and we paid the price."

The blow fell hard here, one of the industry's centers, where peasants for centuries had raised popies and knew no other paying agriculture. Peasants began shifting to sugar beet and other cash crops, but the process was painful. More people joined the tide to the city, while the schools all over the country were becoming politicized by new left- and right-wing teachers more interested in politics than academics.

If agca's mother does not know what her son was reading, others believe that like thousands of Turks from his generation he was probably reading politics from all sides, revolutionary tracts and dogma -- like them, looking for a better life.

When conservative Justice Party leader Suleyman Demirel came to power at the head of a coalition that included ultra-right National Action Party in 1976, the shock waves in Malatya were profound. Recruiting followers from bored and disaffected children here and in other congested cities, the National Action Party's shadowy Gray Wolves underground cells began strengthening and arming, according to Ankara government sources and others here.

Authorities have sifted the party's records impounded after party chief Alparslan Turkes and hundreds of its other leaders were arrested following the military coup last September. They have disclosed no evidence that Agca ever formally belonged to National Action's legal "Idealists" youth groups, but sources here say he was seen in the company of Idealists.

The Gazi slum became one of the party's bastions. "Before the coup, I wouldn't walk here like this without fear of being shot," said a local man of leftist views during a stroll through the neighborhood, a collection of tiny shops and two-story mud-and-brick stucco houses and unpaved streets baked under the spring sun.

Agca stuck with his studies, continuing his excellent grades, his mother said, "If I can get an education, Mother, I will save you," she remembers him saying. "If my father were alive, we wouldn't be like this. But with my studies I am going to be a great man."

His mother wanted him to become a craftsman but he insisted, "No, I am going to become a great man." Even though the family lives in the middle of a National Action Party area, his mother says her son was attracted to the charisma of left-of-center former premier Bulent Ecevit, whose reputation rests on his liberal journalism as well as his politics. She said her son at one point wanted to be a journalist like Ecevit.

Political violence in Malatya, always present through the 1970s with reprisal killings by left and right, suddenly flared on April 18, 1978, when a local Justice Party chief, Hamit Fendoglu, opened a parcel that morning and was blown up along with two grandchildren and daughter-in-law. Three days of pitched attacks, right against left, followed.

More than 700 shops owned by leftists were looted or burned. The violence brought martial law to the province including Malatya, the first to be put under the Army. But the killings escalated in the city, averaging more than 50 a year, accompanied by hundreds of bombings that maimed and terrified.

By the time of the violent upsure, Agca had graduated with top marks from the best local schools and obtained entrance to Ankara University, despite stiff competition on national exams. He seemed posed for the escape he had dreamed of and had promised his family.

But instead of pursuing his studies, Agca abruptly took another course drifting to Istanbul, returning home from time to time to sit silently in his favorite corner, dreaming. "He didn't tell us anything," Mrs. Agca said of her son at that time. "From his childhood days, he did not like to talk. In his letters he could say, 'I am fine. Don't worry.'"

In early 1979, he suddenly told his mother he wanted to visit an aunt in Belgium. He applied for a passport in his own name. A month later, editor Abdi Ipekci fell to bullets fired by Agca. According to the police in Rome, Ankara and here, the man from the violent ghetto of Malatya, who dreamed of becoming a great man, had found a different calling.