When the woman's old boyfriend called to report that he would be coming home from the Army in a few days, she was more nervous than pleased. She ordered her new boyfriend to move out of her Columbia Road apartment right away. He sulked, gave her the silent treatment and left.

But in September 1977, while the woman and her old boyfriend were celebrating their reunion in her apartment, her new boyfriend returned to her building with some matches and a milk carton filled with gasoline.

He set fire to the hallway outside her apartment, turning the staircase into ashes, searing the walls of several apartments, including hers, and converting one neighboring tenant's furniture into charred sticks. He was convicted of arson seven months later and sentenced to two years in prison.

Anger, jealousy or spite between lovers or spouses is the reason for about 40 percent of the arson fires in the District of Columbia, making it the largest single motive for arson in the District, according to D.C. police arson investigators. And the number of such fires has been growing.

"Arson is really a behavioral problem in Washington," said arson detective Donald A. Smith. "Most of our arson stems from psychological problems rather than financial ones."

Just why these problems have been responsible for more of the city's acts of arson in the last several years, experts have a hard time explaining. They cite factors that range from mounting social decay and alienation to the impression made by the burning of downtown stores in the riots of the late 1960s.

The profit motive -- the cause of most arson in movies, television shows and popular lore -- is an insignificant factor in Washington, investigators say, accounting for only about 10 percent of the deliberately set fires here.

In addition, arson investigators say, another 10 percent of arson cases involve personal disputes between people who are not spouses or lovers; 15 percent, mischievous juveniles; 15 percent, pyromaniacs; 5 percent, people expressing racial or religious hatred and 5 percent, families on welfare who want to move to larger apartments quickly.

The arson figures do not include about 1,500 fires a year that are labeled undetermined in origin. Most such fires occur inside or outside vacant, uninsured buildings, and arson investigator Smith theorizes that the majority are set by pyromaniacs or by homeless men and women trying to keep warm.

Since 1970, when arson investigators first became alarmed about how many fires were apparently being set by unhappy lovers, the number of such fires in Washington has increased with each succeeding year. Arson in general has also been rising through this period, although the total number of fires has decreased.

Betwen 1972 and 1977, for example, the number of building fires in the city declined from 3,457 to 3,105, but incidents of arson rose from 263 to 524 and the dollar loss jumped from about $250,000 to about $1,500,000 according to figures provided by the D.C. fire marshal's office.

Anger-related arson involving lovers or spouses went from 90 to 210 cases in the same period.

Fire investigators in Washington's suburbs report a similar pattern. "Our preponderant problems," said Captain Duncan Munro of the Prince George's County Fire Department, "are juveniles who don't have anything to do and adults who have a lovers' type quarrel."

Washington's rising arson rate corresponds to a nationwide trend. National Fire Protection Association figures show there were 40,000 acts of arson in 1966, 144,000 in 1975 and 150,000 in 1976.

No national figures exist on the percentage of arson caused by jealous or angry lovers. But interviews with arson detectives and fire officials from other large cities indicate that Washington is not unusual in the fact that more arson is inspired by anger here than by greed.

Boston, Miami, Detroit and Chicago all report similar trends. "We don't have that many fires where we can even speculate that people were trying to make a profit," said Chicago police commander Edward Nickels of the arson squad. "Our biggest problem is the anger fire."

An exception to the pattern is New York City, where fire marshal Joseph McCormack credits 90 percent of the city's arson to the profit motive. McCormack believes New York is less stable financially than most other large cities, and argues that the incentive to commit arson is greater when businesses or apartment houses operate at a loss.

Washington's arson problem has fallen into a depressingly repetitive pattern. It is a pattern of rejection, hurt and revenge -- usually set off when one partner decides to have an affair, or to end a romance before the other is ready to call it quits.

On April 12, 1978, Joyce Mack, 24, who was separated from her husband, burned the walls, bed and kitchen curtains of his Fourth Street NE apartment. She was later convited of destroying property and sentenced to three months in jail.

And then, in July and August 1977, there was the case of the man who refused to have sex with his wife, believing she had been having an affair with a woman friend. On an August night in 1977, his wife, decided she wanted to discuss his lack of interest. But her husband refused to talk to her.

"Damn it, why don't you talk to me?" she screamed at him, according to a statement she later made to police. She then ran to the porch of their two-story frame apartment building, where she picked up a gallion of gasoline, brought it into the bedroom and doused the mattress with it, according to the statement.

"I got the matches and struck them and threw them on the bed," she said in the statement. "I was still hoping he would stop me but he didn't. I didn't think the fire would flash up so fast. I told him to get the baby out and I started banging on doors to get people in the other apartments out."

Within minutes, the fire had spread from the mattress throughout the apartment, gutting the apartment and causing smoke damage to two other apartments in the building.

The woman was convicted of a felony charge of destruction of property and sentenced to one to three years in jail, but her sentence was suspended. She was not convicted of arson. Police asked her husband to make a statement against her, but he refused to talk.

Cases like this were much less common before 1970, but behavioral scientists and arson investigators explain the shift differently.

The chief of the forensic psychiatry division of the city's mental health administration, Dr. David Lanham, believes that all types of violence have been increasing and that arson involving lovers or spouses is just one of them.

"In a tight community, violence hapens person to person," said Dr. Martin Stein, medical director of the Dominion Psychiatric Treatment Center in Falls-Church. "When there isn't strong social fabric, people choose indirect means for violence. This pype of crime may be a sign of social decay."

Arson investigators offer their own explanation.

"Before 1968, it was very unusual to have a spite fire," said Smith. "People became umch more conscious of fire as an outlet for anger when rioters were burning the stores downtown."

In Los Angeles, where anger or jealously accounts for 38 percent of the arson fires and profit accounts for only 3 percent, Fire Department Capain Partrick McGinnes offers a similar explanation. "It used to be that someone would get mad at somebody and punch him around. But after the Watts riots a lot of people discovered that a sneaky way to get even was to burn out the enemy."

Psychiatrist Lanham calls arson a coward's crime. "Arson is a particularly sneaky way to get even with someone," Lanham said. "The person doesn't have to face anyone with a gun or a knife. Think of the old saying, "There ain't nothing lower than a barn burner."

Lanham believes people who set fire to an apartment to vent anger are "usually passive people who have no adult, mature ways of expressing their aggression. In some of these cases, people get erotic satisfaction and excitement out of fire setting. "There's a sexual component to fire setting. Think of that song, 'Baby Won't You Light My Fire."

Fire, symbol of passion, is used by lovers against each other because it helps them compensate for feelings of impotence, according to psychiatrist Stein. "If you're being pushed around, you can set fire to something and feel as though this massive conflagration is all you, and all these fire trucks are out because of you. It restores a feeling of power to some people."