A Swiss court issued an order yesterday attaching a Swiss bank account containing "virtually all" of the $1.5 million embezzled last month from the Washington area's largest money market fund.

Officers of the fund, First Variable Rate Fund for Government Inc., are "taking all necessary further action to promptly effect the return" of the money, frozen in an account at the Union Bank of Switzerland.

Wayne Bardsley, secretary and general counsel of First Variable, said yesterday it may take "a month or more" to effect the return, but that neither the $788 million fund nor its shareholders would be affected adversely. n

"The fund is insured against such potential losses and, furthermore, the fund's adviser, Government Securities Management Co., has agreed to assume any costs or expenses which may not be recovered by the fund's insurance policies," he said.

FBI agents still are searching for former fund employe Vera Lucia Campos and for Andre L. Prestos in connection with the case.

According to papers filed by the fund in federal court on May 5, Campos allegedly transferred $1.55 million of fund money to an account belonging to Prestos. Two days later, Prestos withdrew $50,000 of that money in cash, the court papers say.