BALTIMORE, MARCH 3 -- A federal grand jury today indicted three former officers of First American Mortgage Co., a Baltimore brokerage firm, on charges of conspiracy and mail and bank fraud.

The nine-count indictment charged the three with scheming to defraud five out-of-state banks and savings and loans out of $5 million.

They are Jerry L. Gaultney, 53, of Potomac, FAMCO's former president; Thomas J. Polvinale, 40, of Phoenix, the firm's former chief financial officer; and George Schnabel, 33, also of Potomac, FAMCO's former vice president.

The indictment alleged that the three assigned uninsured, "frequently delinquent, paid-in-full or otherwise inadequate" mortgages to multiple investors between July 1984 and November 1985, when FAMCO filed for bankruptcy and closed.

The company had been founded and operated by Michael H. Clott, later convicted of fraud.

The schemes alleged in today's charges are similar to those Clott operated before he moved up from the presidency of FAMCO to become the company's chairman. Clott is named as an unindicted coconspirator in the case.

Clott swindled nearly 300 investors out of at least $15.7 million by brokering high-risk mortgage packages to investors nationwide through FAMCO.

The upheaval from his schemes prompted a variety of civil lawsuits among companies that did business with FAMCO, including cross-suits between E.F. Hutton Mortgage Co. of New York and Equitable Bank of Baltimore.

Clott, who pleaded guilty to federal charges in two cases last year, is serving a 12 1/2-year federal prison term for racketeering, interstate transportation of stolen securities and mail fraud.

Prosecutors Breckinridge L. Willcox, Jane F. Barrett and Dale P. Kelberman said in a news release today that no arraignment date has yet been set for the defendants in the new case.