For the past five months, Arthur Chariton, a 55-year-old Miami businessman, has sat in a cramped and rat-infested cell in the Managua city jail, contemplating hanging himself and cursing the day he ever decided to come to this steamy Central American outpost.

His reason, pure and simple, was money. Two-and-a-half years ago, Chariton joined in a 50-50 partnership to manufacture textiles with Nicaraguan President Anastasio Somoza, who runs a wide-ranging business empire in addition to his political duties.

oday, Chariton says, Somoza controls all his Nicaraguan assets, following their confiscation by Nicaraguan courts. The president has refused to meet with his jailed former associate.

Convinced that his situation could not be any worse, Chariton denounces the president, who he once "liked and had faith in," as a "selfish bastard and vicious man."

Chariton charges that the has been framed with trumped-up charges of fraud, embezzlement and theft, in an attempt to blackmail him for $1 million for his release.

Besides throeing him in jail, he alleged, Somoza's thugs have threatened his family in Miami with physical harm if they do not come up with the money.

A diabetic, Chariton says that at times he has been denied medical care in jail and that once when he was permitted hospital treatment, he was dragged out of his bed shortly after, wearing only undershorts and without shoes, by soldiers who put him back in his cell.

Regardless of his guilt of innocence, there is little question that Chariton is a man who got in over his head in a county where he didn't know all the rules of the game.

he cardinal rule here, informed observers say, is that Somoza's power is absolute. The president, whose family has controlled this country of 22 million people politically, militarily and economically for most of the last 40 years, can do whatever he wants to do, to whomever he wants to do it.

On the surface, the partnership seemed like a sure-fire deal. Since Somoza, by virtue of his position as president and head of the Nicaraguan military forces, controls government concessions for foreign businesses as well as custom and immigration police here, there were no anticipated red-tape problems.

Since Somoza, believed to be the richest man in Nicargua, with interests in more than 100 companies, has had a number of successful business partnerships with other foreigners and already ran a textile factory, there seemed to be no prospective difficulties with financing and sales.

The Chariton case, however, is one indication that Somoza, 51, who is in poor health and recently suffered a heart attack, has perhaps been spreading himself so thin that he can no longer keep track of his many enterprises.

A complex web of financial finagling the case boils down to the possibility that one Somoza company may have been cheating another. It involves a check-kiting scheme, allegedly perpetrated by another Nicaraguan associate of Chariton and Somoza, designed to embezzle an estimated $3 million from the Managua-based Bank of Central America.

Somoza owns a controlling interest in the bank.

The president said one source close to the case, "thinks he has been ripped off" and hasn't shown much interest in listening to explanations.

Among the heads that have rolled so far are those of Chariton, who maintains he had nothing to do with the checks: E. S. Dudkewicz, a U.S. citizen and longtime Somoza classmate at West Point.

While Chariton and Picado Laara are jail cell neighbors. Dudkiewicz has reportedly fled the country:

If and when Chariton's case comes up for judgement, he could get a prison term of up to 10 years if found guilty. But he fears that different rules might apply or none at all.

"When you talk about what they can do to you here . . ." he said, "they cando anything they want."