Juan Argueta's problems were only beginning when he and 13 other illegal aliens were arrested at Blackie's House of Beef last Friday.

Without any money to post bond or to pay his way home voluntarily, he opted for an immediate hearing and Monday was ordered deported to E1 Salvador. He told immigration officials that is where his family lives.

But when two immigration agents accompanied him to his home on upper 17th Street NW to pick up his meager personal effects, they were in for a surprise.

The door was ajar and when they went in they found not only Argueta's wife, but another couple as well - all from E1 Salvador, all illegal - and a baby who had been left with her friends by the mother.

While this group was being questioned there was a knock on the door. Two men showed their faces for a second, someone in the apartment shouted that "la migra" - the Immigration Service - was there and the two took off running. One was caught, the other got away.

The INS investigators left one woman to take care of the baby and took the others to headquarters where they, too, now await deportation.

Asked about the fate of the people they apprehend in a raid such as the one on Blackie's, U.S. Immigration and Naturalization Service officials always emphasize the need for discussing each case individually. As one investigator put it, "Sometimes they sound the same, but they're never exactly alike."

Of the 14 people picked up at Blackie's eight have now been released on bonds ranging from $500 to $2,000. Some had saved the money, others had borrowed it from friends.

Two of the men picked up Friday had been arrested and deported before. Because they reentered the United States illegally they now are subject to felony charges that could result in two years imprisonment and $1,000 fines. They are in the custody of U.S. marshals and yesterday appeared in District Court where their bonds were set at $10,000 and $15,000.

Two others are being held until attorneys can be found for them to assist indeportation hearings and bond hearings.

Two of the original 14, Argueta and a young Thai named Prasit Vatanavalar, will be flown out of the United States today. In their two stories alone can be seen the enormous contrasts existing in Washington's illegal population, which is as diverse as any in the country, numbering 100,000 to 150,000 in the metropolitan area, according to informed estimates.

Vatanavalar said as he sat in the deportation office at INS district headquarters yesterday that he had come to the United States five years ago as much for adventure as for money.

He told a reporter in clear English that he had had good jobs in Bancock, including a position in a travel agency. He had come to the United States on a student visa to study at a language-teaching branch of the Lacaze-Gardner school in 1973, but he said he never had any real intention of studying here. "What would I get if I graduate, just learning English?" So in 1974 he went to work at Blackie's.

Though he would not talk about them, friends of Vatnavalar said that his wife eventually joined him here and they now have a child born in the United States.

When Blackie's was raided in March, Vatnavalar was one of 10 illegals picked up. He was ordered to leave the country voluntarily by Aug. 7, but never did. This thime he was not given a choice.

He chalks it all up to experience, he says. His wife and child soon will join him in Thailand and maybe he will be able to get an even better job there now. But first, he says, he will enter a Buddhist temple for "three of four months," shave off his fashionable long hair and "clean all my thoughts" of life in America.

Juana Argueta, Juan's wife who was picked up in their apartment Monday, told a very different story. Speaking in Spanish, because she had learned almost no English in the eight months she has worked here as a servant for an officer at Andrews Air Force Base, she said that she and her husband had saved for years to be able to come to the United States.

He was making less that $2 a day in E1 Salvador, she less than $15 a month. He made the journey first, then a couple of months later she followed, leaving their 2-year-old boy with her mother.

It cost her $250 to be smuggled across the border form Tijuana, she said, and another $350 to be driven nonstop across the United States to Washington in the back of a van.

"Life here was never very happy," she said, "because we were always thinking of the family in E1 Salvador, always thinking about work here."

When she saw that "la migra" was going to take her away, she said, "I thought, 'We are poor. We are losing so much money. It has cost us so much to come here that when we go back we will be poorer than we were before."