A Maryland state judge has ruled that statements former vice president Spiro Agnew and others made to federal prosecutors in 1973 can be used against them in a lawsuit seeking to recover $200,000 in kickbacks they allegedly received.

Anne Arundel County Circuit Court Judge Bruce C. Williams has held that sworn statements made by Agnew, Jerome Wolff, and I. H. (Bud) Hammerman to the prosecutors may be introduced in a case filed by three Montgomery County taxpayers.

The suit, filed in 1976, argues that kickbacks discovered in the corruption probe that led to Agnew's resignation as vice president resulted in taxpayers' having to pay inflated prices for highway engineering contracts. The payments should be turned over to the state treasury the suit says.

State Del. David Scull (D-Montgomery), a lawyer for the taxpayers, yesterday called the decision "a very big step forward for the suit. The essence of our case is proven by those [sworn] statements." Defense lawyers could not be reached for comment.

In January 1979 Judge Williams ruled that the Fifth Amendment's protection against self-incrimination meant Agnew and the others could not be forced to testify about the alleged kickbacks.

Had their earlier statements been ruled inadmissible, Scull said his clients would have the difficult task of reconstructing the kickback system with independent testimony.

"We would've had to find secretaries and engineers who were willing to testify. Of course, many of the engineers involved might've been fearful of further prosecution," Scull said.

According to Judge Williams' decision, the taxpayers still have the burden of proving "that the actions of the defendants have injured and specially damaged them" as individuals.

Courts in several states have endorsed the concept that taxpayers can sue on a wide number of issues involving public money, Scull said.

In an effort to bolster his argument that the kickbacks led to increased taxes, Scull said he is considering asking the state to join the suit on the side of the plaintiffs. Similar requests were rejected in 1976 and 1979, by the state attorney general's office.

The idea for the suit sprung from a legal activism class at George Washington University law school in 1973, the year Agnew resigned as vice president. John MacMillan, a student in that class who now lives in Montgomery County, and two other county residents filed the suit in October 1976.

The legal costs of the suit have been borne by the Fund for Constitutional Government, a Washington-based public interest law foundation funded by liberal philanthropist Stewart Mott.