Tensions between strikers at the Cambridge-based Cambion Corporation and newly-hired non-union employees heightened last week when Sandy Polaski, president of the union, and two others were arrested for allegedly throwing rocks through the window of a non-striker's car.

Just a week earlier, four Cambridge police officers were suspended without pay for 35 days by City Manager James L. Sullivan over an incident last May during which striking workers alleged police "brutality."

The police were called in by management officials to allow a company truck to leave the property. When the police opened up the crowd of strikers to let the truck through, strikers alleged that the police used unnecessary force in clearing the way.

Investigations

Soon after the workers made their allegations, the police department internal affairs division conducted its own investigation of the charges. Sullivan considered the report unsatisfactory and began his own investigation, which resulted in the suspensions of the officers.

Cambion, which employs about 400 workers, manufactures computer components and parts for integrated circuits. The U.S. Defense Department is its biggest contractor.

Polaski expressed concern yesterday that there might be more trouble as an increased numbers of picketers and police face each other this morning. She also indicated that 15-20 riot policemen had been put on alert at the Fresh Pond police station, and said that they were "going through maneuvers."

Acting Cambridge City Manager James Healy is scheduled to be there to observe the action of the picketers, strike-breakers, and police.

The union, Local 262 of the United Electrical, Radio, and Machinery Workers, has been on strike since April 14, when the first year of a two-year contract 6A