The Law School will terminate its contract with the Harvard Police Department's security guard unit next month and use a private firm for security patrols, officials said this week.

The move, the latest in a series of changes which has seen private companies take business from Harvard's in-house security force, will be announced in next week's issue of the Law School Advisor. Officials at the school said the hiring of the private firm, Security Systems Inc., will cut security costs by one-third and allow for greater control of security forces.

Paul Upson, assistant dean of financial operations at the Law School, said a four-person committee of which he was a member approved the switch because it gives the school "more control" over its own security.

"The management of a for-profit firm will be more responsive to our input," Upson said.

The Business School and the Medical School have also dumped the University's security services in favor of Security Systems. Several Harvard museums have terminated contracts with the guard unit, and Harvard Real Estate has also contracted with a private firm, Pinkerton Security, for its new Shops by Harvard Yard complex in Holyoke Center.

Harvard security officials referred all questions to Acting Police Chief Lawrence J. Murphy. Murphy said he anticipated no layoffs in the Harvard guard unit, and he had no further comment.

Security Systems is able to offer a lower price because it pays significantly lower wages than the University guard force, sources familiar with the situation said.

Upson said the change was not motivated by recent allegations that two Harvard security guards stole water coolers from the Law School.

Last summer, Vice President and General Counsel Margaret H. Marshall released a report after 11 former and current security unit employees alleged that there was racial discrimination in the unit.

The Marshall Report said that competition with outside companies was forcing the University's guard unit to cut costs, leading to problems between management and guards.

But the report suggested that outside agenciesmight do the job at a lower cost and with fewerinternal problems than Harvard's own securityunit.

Frank Lamantea, director of building operationsat the Law School and a member of the four-personcommittee, said officials there had beenconsidering a switch for several months.

Upson said the committee interviewed fivefirms, including the Harvard in-house securityguard unit. The decision was made after visits tothe various firms, he said.

Security guards' duties include opening doorsand monitoring buildings. The Law School willcontinue to be served by the Harvard UniversityPolice Department, whose officers carry guns andare trained to handle more dangerous situations