One of the Landover Mall security officers who three Prince George's County youths allege beat them after arresting them Saturday has a$6 million civil assault and battery suit pending against him from an arrest incident at the mall in 1982.

Mall spokesmen said that any injuries to the youths Saturday were the result of resisting arrest and denied the three were beaten after being taken into custody. Shoppers in the mall said they witnessed some of the confrontations. A D.C. police officer, who said he had seen one of the Saturday incidents, yesterday questioned the tactics used by the security guards.

Among the privately employed security guards being accused by the youths of beating them is special police Officer Gary F. Byrd. According to records at the Prince George's County Courthouse, Byrd also is alleged to have thrown Larry J. Day against a pillar in the mall in 1982 after the man refused to leave. Day's suit for $6 million against Byrd and Lerner Corp., which owns the mall, claims that Day was assaulted in the course of being falsely arrested, imprisoned and prosecuted. Day's case is scheduled for trial in June.

In a written response in the file, Byrd said he asked Day to leave because his breath smelled of alcohol and he was bumping into other customers. Byrd, who has arrest powers while on mall property, charged Day with disorderly conduct. The officer said he did not strike Day, but he and other officers had to restrain him to "protect ourselves from injury because of his striking and kicking at us."

Last Saturday evening, Byrd and other guards arrested Eugene Darnell Thompson, 18, and his nephew John Thompson Jr., 16. In an unrelated incident a short time later, Mark Gibrau, 20, also was arrested by Byrd and others. The three youths were charged with trespassing, disorderly conduct and resisting arrest. All three claimed they were handcuffed, then beaten by the officers.

Yesterday, mall officials declined to talk further about the incidents Saturday or mall security in general. Attempts to reach Byrd were unsuccessful.

D.C. police Officer Percell Gregory said he was shopping at the mall on Saturday with his family and heard Gibrau telling security guards not to be rough with a girl who had just been arrested at a snack stand. Gibrau and the guards began arguing and one guard said to his coworker, " 'Look, don't argue with these people, take him upstairs,' " Gregory said.

At that point, Gregory said, one of the guards pushed Gibrau against the window of a shoe store. "One had him around the throat in the crook of his elbow," Gregory said, and another officer struck Gibrau in the groin. Gregory said he did not see where the guards took Gibrau after that. Although Gregory said he did not interfere in the arrest, he criticized the method of restraining Gibrau and said it left witnesses "flabbergasted."

Gregory, who lives near the mall, said he has never seen a fight in the mall before, but he often notices the behavior of the guards. "They're not polite at all," he said.

A former Landover Mall security guard, who asked not to be named, said he believes the mall is a difficult place to work and that guards are not adequately prepared for the rough circumstances there. The man, who worked at the mall until recently and who said he quit because he did not like the "techniques" used by the security force, said injuries to those arrested is not unusual. He also said the mall security job requires six months of security experience or military experience, but he said he believes that is not adequate.

Shopkeepers at the mall offer mixed reviews. One store worker said the guards sometimes seem "unprofessional." But Nan Chun, manager of Kay Jewelers said he was surprised to hear about the recent fights. He contends that the guards have a difficult job. "Some of the teen-agers can be pretty rough," he said, but added that as paid employes, the guards "should try to control their tempers."