The first night back in Cambodia, I could barely sleep. So I arose early with the idea of taking a walk-without the guards who had followed me around the first day-to see for myself what had happened to the city which once was my home.By 6:30, I was out the front gates of our guest house undetected, and I started to stroll up Monivong Avenue, one of the main boulevards of the capital. People were out on the streets, mabye a dozen on each block, all dressed in black with bright, checkered scarves around their necks.

It was familiar but skewed. During the war, the streets would have been unmanageable with motorbikes, pedicabs and cars. That morning, I could have walked straight down the middle of Monivong Avenue.

A cluster of young men sat on a curb, waiting, it turned out, for a truck to take them to a factory. I stopped and tried out my rusty Khmer. I explained that I was an American journalist and asked how things were going.

What smiles. Fine, they answered, taking a close look at me. Heir ride appeared, and I continued north up the street, passing former apartment houses and a high school which apparently being used for dormitories.

I had heard all the stories of how Phnom Penh-a city of almost 3 million people by the time the war ended-had been turned into a virtual ghost town by the country's new Communist rulers.

There were certainly indications that its population had greatly diminished. In the commercial area, near the old Central Market, very few offices were in use. But the new government seemed to repopulating Phnom Penh in a checkerboard fashion-some blocks occupied, others deserted.

I walked past the market, which now has banana trees densely planted around its empty stalls. Gardens seeded with vegetables and young fruit trees had replaced the front lawns of many deserted homes on side streets.

I came to the orphanage where I had worked on Sundays during the war. It, too, was empty. So were the restaurants and small hotels farther up the road.

At last, I came to the Hotel le Phnom, my former home. Something was missing. The grand stone French cathedral that had stood diagonally across from the hotel had disappeared. Two cows were grazing on what was now a vacant lot.

I had to see the inside of the hotel, especially my old room. After exhcanging greetings with the guard stationed at the door, I walked in.

It was almost the same. The wood was polished, and posters of Angkor Wat hung in the lobby, but the reception desk was not in use. Money is no longer used in Cambodia.

As I headed back to the government guest house, hopting to get there before my absence was discovered, I tried to hitch a ride.

A young man on a motorbike stopped, and I was just about to climb on the back when one of our guards came bicycling furiously down the street shouting.

The guard told me to wait, and soon a Mercedes came for me. Our official guide admonished me for going off on my own, and asked that I not venture out by myself in the future.

"You don't understand but we are in a situation of war." Thiounn Prasith said, "I don't worry about our own people, but we are at war, and we have many enemies."

Cambodia's war with Vietnam at that point seem miles away, and I viewed this is not very subtle way to ensure that I only saw what the government wanted me to see.

But on our last night in Cambodia, 13 days later, I realized in the most sorrowful way that Prasith was right. At least one terroist broke into the guest house where we had spent that first night, and murdered Malcolm Caldwell, the British scholar who was one of our three-member party.

At Thiounn Prasith grieved over Caldwell's death that last day, repeating how very sorry he was that such a good man had been murdered, he shook his head at me.

"I told you we had enemies," he said.

Until that final night, we had felt very little sense of being in a country at war.

In travelling more than 1,000 miles around Cambodia with Caldwell and Richard Dudman of the St. Louis Post-Dispatch, I was more interested in trying to find answers to the grave human-rights accusations that have been leveled at the country's Communist rulers over the past three yeears.

More than 100,000 refugees have fled Cambodia since the Communist victory in April 1975, and many have told harrowing tales of how thousands-some experts say hundreds of thousands-of people have been killed in what many describe as the greatest systematic slaughter in modern history.

Before setting off on this trip, I studied the volumious documents submitted by the United States, Great Britain and Canada to the U.N. Commission on Human Rights. I also visited a Cambodian refugee camp at Aranyaprathet, Thailand, to better prepare myself for trying to find out the real situation.

During my stay in Cambodia, I made repeated efforts to find people who had been among the hundres of thousands reportedly driven out of Phnom Penh immediately following the war, and herded on forced marches into the distant countryside. Many are said to have died on these marches.

But in entire visit, I was allowed to talk to only two former inhabitants of Phnom Penh-both of whom said they had left the city voluntarily.

I also did not see any signs during my visit of mass graves. For all that I saw and heard, I have no definitive answers to many troublesome questions.

But clearly, many people died during the first years of the new government, and during a conversation with Deputy Prime Minister Ieng Sary, he gave the most open response of the Cambodian government to date.

"Frankly speaking about the so-called slaughter, the massacres, we could not avoid the killings," Ieng Sary said. "But in comparison with the complicated situation in Kampuchea after the war, the Communist Party of Kampuchea has solved this problem with a good solution-avoiding many more killings if they had to take another solution."

"Maybe that is not your belief," he added. "but we are responsible and we grasp the real situation in our country."

The situation that they most wanted to talk about was their current war with Vietnam.

In traveling about the country, we saw little evidence to support the widespread belief of Western and Asian diplomats that Vietnamese troops are taking over large chunks of the country.

Only when we were traveling in border areas-like the day we visited the village of Krek, little more than a mile from Vietnam's Tayninh Province-did we even hear rifle shots or cannon fire.

But to judge from the concern of Cambodian leaders the military situation facing the Phnon Penh government must be more serious than anything we saw on what was admittedly a limited, two-week visit would indicate.

"At present, this problem is a problem of life and death for us." Ieng Sary said. "That is why we talk about it."

At a dinner he hosted for us one evening, he even admonished us for failing to ask enough questions about the war. "Vietnam is carrying out all kinds of maneuvers against us," Ieng Sary said. "Including political assassinations."

Beyong impressing us with the reality of the war, the Cambodian leaders were also anxious that we get first hand look at what has to be one of the world's most bizarre revolutions.

An idea that struck Caldwell one afternoon we neared the end of a long-day may, in fact, capture what is taking palce in Cambodia best.

"That's it," he suddenly exlaimed, "A book title-'I have seen the past and it works."

Certainly, it seems as if Cambodia has indeed taken a deliberate step backwards-away from modernity-and is shunning the advances of the industrial revolution in tis effort to become a self-sufficient agricultural nation.

On the whole, I must also report that most of our journey was a government-guided tour about which we had little say.

On our first day in Phnom Penh, we were each asked what we would like to see.

I listed many preferences, I proposed that I talk with Prince Norodom Sihanouk and former Presidium president Khieu Samphan, and also asked to visit agricultural cooperatives in the countryside with former residents of Phnon Penh.

None of these requests was honored. But they did agree to some of my proposals, and had a few surprises of their own.

One day early in our stay, we were taken to the former military headquarters of FANK, the army of Lon Nol. It was a building I knew well from attending a year and a half of briefings during the war.

It was heavily guarded in those days, and barbed wire was the only ornament on its lawns. Today it is a museum, while the offices of former FANK commander-in-chief, Gen. Sosthenes Fernandez, have been tidied, they basically remain the way they were found on April 17, 19759

Our guide at the museum was Loan, a 23-year-old solider who fought in the final siege of Phnom Penh. He was the diminutive as Fernandez, and I had a feeling of deja vu as he took the same place in the briefing room that the general preferred, and picked up a pointer to explain his side of the war.

"This map," Loan said, "shows the situation of the friends-that means the 'situation of the enemy'-that is us-that is our situation when we won."

For a brief moment, the world did a flip-flop. It was a sesation I was to experience regularly during my two week journey through Democratic Kampuchea. CAPTION: Picture 1, Farmers returning home from the fields in northwest Cambodia: The nation's new rulers appear to have deliberately avoided trying to use modern technology in their attempt to become agriculturally self-sufficient. By Elizabeth Becker-The Washington Post; Picture 2, A Cambodian guard at a monument in the Angkor complex: "We are at war."; Picture 3, Villages building homes: An agricultural cooperative in northwest Cambodia; Picture 4, Children carrying firewood in northern Cambodia: Very little sense of a country at war. Photos by Elizabeth Becker-The Washington Post; Map, no caption, By Dave Cook-The Washington Post; Picture 5, Khmer villager, left, and official Thiounn Prasith: ". . .we have enemies."