West German police had their first break today in a terrorist murder case that has shaken up the public, press and politicians.

A 23-year-old woman, Eleonore [WORD ILLEGIBLE] Poensgen, who was arrested in Frankfurt yesterday, was identified by a widow of slain bank executive Jergen Ponto as having taken part on Saturday night in the attempted kidnapping that turned into a murder, funeral authorities said.

The slaying of Ponto, who was head of the Dresdner Bank, the second biggest in West Germany, has jolted his country because the banker was the third prominent figure gunned down by anarchists in the past three years and the first who was not [WORD ILLEGIBLE] with the government.

This has opened up the possibility that Bonn's already burdensome job [WORD ILLEGIBLE] providing protection for potential [WORD ILLEGIBLE] of terrorists in the government, judiciary and security agencies, may now have to be extended to prominent figures in the private sector.

Today, persons identifying themselves as members of the "Red Morning" organization and claiming reponsibility for the murder called news agencies to demand immediate release of all imprisoned urban guerillas, calling them "political prisoners of war."

If that demand is not met, they said, "more members of the exploiting class will be executed."

Both government and opposition politicans today called for beefing up West Germany's already large police forces for the fight against political extremists.

The tone of editorials in several newspapers, including the respected Frankfuter Allgemeine, is becoming increasingly strident, reflecting the strain that the new murder is putting on Germans looking for explanations.

Just four months ago. West Germany's chief federal prosecutor. Siegied Buback, was gunned down on a Sarlsruhe street, and in November 1974, the West Berlin Supreme Court President, Judge Guenter Von Drenkmann, was shot at point-blank range by terrorists who, like the group that called Ponto, came to the door with a bouquent of flowers in hand.

The Frankfurt newspaper compared the political protests after the Buback killing with the ones being heard now and lamented that "such repetition reflects helplessness toward fanatics who are difficult to curb with constitutional means."

Although there is far less crime here than in Italy or the United States, for example, the West Germans - because of their past - are particularly question of dealing with it in a democracy.

They face demands for citizen protection and law and order on one hand, yet occasionally display a tendency to overreact to terrorists by passing very strict new laws or increasing police authority. This, in turn, yields charges by extremists of neo-fascism and more well-meaning critism by some civil libertarians.

Still, West Germany appears to breed a particularly virulent form of terrorist, and the murder of Ponto has also shaken up authorities because it shows that groups willing to kill are still at large despite considerable police success in breaking up such gangs in the past two years.

The woman arrested in Frankfurt - who has denied involvement in the case - is not the principal figure being sought in the nationwide search for Ponto's assassins. Police have a murder warrant out for 26-year-old Susan Albrecht from Hamburg, a daughter of a friend of the Ponto family, and six other alleged accomplices, several of them women.

The latest killing has also renewed the West German search for an explanation of the extraordinarily high percentage of women involved in anarchist and terrorist activities here.

The Ponto killing, coming so close to the Buback slaying, has also unleashed a less restrained and potentially ugly assault on the alleged large number of leftist sympathizers in the universities.

The attack has included editorials in the independent Frankfurter Newspaper. The more conservative Die Welt said that West Germany will never be able to deal with terrorism "as long as it subsidizes the mentality of violence in the schools."

Today, a major figure in the opposition Christian Democrat Party, Alfred Dreffer, deplored the resort to politically motivated killings and also blamed it on Marxist influences in the schools.

In Stuttgart, however, newspapers warned against "incredible generalizations" and the respected Suddeutsche Zeitung in Munich concluded that "only when the politically speculative placing of blame stops, can the democratic solidarity emerge that will make it possible to deal with terrorism and its equivocating defenders."