Two former Houston policemen on trial for beating and drowning a Mexican-American prisoner in their custody last May were convicted by a jury today of misdemeanor charges that will cost each no more than a year in jail and a $2,000 fine.

The widely publicized case was moved on a change of venue to Huntsville, a town of 20,000, about 70 miles north of Houston. It is the headquarters for the Texas prison system. All of the jurors were white, none was Mexican-American and five either worked for law enforcement agencies or had relatives who did.

Outraged Mexican-American spokesman immediately called on the U.S. Justice Department to prosecute the case in federal court as a civil rights violation, for which the officers could receive up to life in prison. However, Houston's police chief issued a statement saying that "the processes of justice have prevailed over demagoguery."

The jury heard four weeks of testimony alleging that six police officers had taken Joe Campos Torres, 23, a laborer, from a cheap cantina, where he was arrested for public drunkeness, to a secluded spot near a bayou, where five of them beat him severely while his arms were handcuffed behind his back.

After a jail booking officer refused to accept Torres because of his injuries and ordered him taken to a hospital, the officers returned to the secluded spot, where one of them allegedly pushed him over a 17-foot embankment into the water after saying, "Let's see if this wetback can swim."

The convicted former officers are Terry W. Denson, 27, and Stephen Orlando, 22. Two of their fellow officers were given immunity from prosecution in return for their testimony in state court against the pair; one other officer faces related misdemeanor charges, and one, a rookie who reported the incident to superiors, remains on the 2,900-member Houston police force.

Denson testified that Torres had said he could swim and had jumped into the water. But Glenn L. Brinkmeyer, 25, one of those given immunity and an officer in whose wedding Denson had served as a groomsman, testified that Denson had pushed Torres.

Brinkmeyer said Denson previously had boasted throwing a wino down a ravine and had beaten other hand-cuffed prisoners.

Testimony indicated that Oralando, who drove the patrol car in which Torres was transported, had encouraged Denson by "this would be a good time" to see if "the wetback" could swim. Torres, an American citizen and a former serviceman, was wearing combat boots at the time of the fatal plunge.

Torres' mother was quoted as saying, "If five Mexican killed a cop, it wouldn't be like this."

State Rep. Ben Reyes of Houston, also a Mexican-American, called the verdict "pathetic" and "the worst miscarriage of justice that I've ever seen." He said it demonstrated once again that there is "a dual standard of justice" in Texas, adding, "Our only redress in the federal courts."

Reuben Bonilla of Corpus Christi, who heads the League of United Latin American Citizens (LULAC) in Texas, called the verdict "the most deplorable and unconscionable in recent memory," and said he fears Hispanic-American violence unless the Justic Department acts promptly to bring a federal case against the officers.

Hector J. Garcia of Houston, chairman of the Coalition for Responsible Law Enforcement, whose group has been meeting with police officials since last April, said violent police incidents here show no sign of abating.

Garcia said there had been progress in that Chief Harry Caldwell has required officers to register the extra weapons they carry with them, has banned the use of "long rifles" such as deer rifles, and has forbidden officers to shoot at fleeing suspects who aren't threatening their safety or that of others.

Nonetheless, Garcia said he is distressed by incidents, including the recent shooting deaths of a black police erroneously believed to be an armed robber and of a 16-year-old unarmed Mexican-American burglary suspect.

In the case of the burglary suspect, Garcia pointed out that a 14-year-old witness had disputed the officer's claim that the suspect had lunged at the officer. The 14-year-old was cowering against the wall when he was shot.

"The environment that created the Torres case continues to exist," Garcia said, "and we can expect a continuation of the same kind of thing."

The two officers convicted in the Torres' case are expected to be sentenced within a few days.

Their convictions were for criminally negligent homicide, a first-degree misdemeanor.