Berlin prosecutors say the suspect in the stabbing of prominent physician Fritz von Weizsäcker admitted to a "delusional general aversion" to the victim's family.

However, there had been no prior contact, according to Martin Steltner, spokesman for Berlin city-state's prosecutors office.

The victim — a 59-year-old liver and hepatitis specialist — was the youngest son of Germany's reunification President Richard von Weizsäcker.

The 57-year-old suspect was diagnosed with an "acute psychiatric illness," and sent to a secure unit.

What do we know about the motive?

Prosecutors did not elaborate, but the news magazine Der Spiegel speculated that the suspect held the doctor's father responsible for "Agent Orange" used by the US during the Vietnam War.

The late Richard von Weizsäcker was German president from 1984 until 1994. Prior to his political career, he was a manager at Boehringer, a chemical company and supplier of components used in Agent Orange. He later spoke of his "distress" at finding out about the defoliant after he had left the firm.

The tabloid newspaper Bild said the suspect, identified only as Gregor S. under Germany's privacy laws, regularly visited Thailand, and had an affinity to the Vietnamese people.

Public broadcaster SWR said police had searched the suspect's home, described as a "rundown apartment" in a housing block in Andernach, a small town on the Rhine river.

What happened during the attack?

During police questioning, the suspect said he had planned the attack in advance.

He had spotted an internet announcement a day before von Weizsäcker held a lecture at Berlin's private Schlosspark Klinik. He then made a 600-kilometer (400-mile) train trip to the capital from his home in the western state of Rhineland-Palatinate.

Towards the end of von Weizsäcker's address, the suspect approached the podium and stabbed him in the neck. Despite efforts by medics, von Weizsäcker died of his injuries.

Around 20 guests at the lecture helped to apprehend the assailant.

An off-duty police officer also suffered serious injuries but is reportedly recovering.

The victim was 'open-minded'

Weizsäcker family biographer Hans-Joachim Noack told Spiegel that Fritz von Weizsäcker, a physician and father of four children, was "open-minded and fun-loving” and an "ardent enthusiast” of artificial intelligence.

"He appeared to me to be the most modern of this extended family,” said Noack.

"I thought he was wonderful,” environmental scientist and cousin Ernst Ulrich von Weisäcker told Germany's dpa news agency.

'Terrible blow,' says Merkel

Steffen Seibert, spokesman for Chancellor Angela Merkel, described the fatal attack as a "terrible blow” for the Weizsäcker family and expressed condolences.

Berlin city-state Health Senator Dilek Kalayci said she condemned "uttlerly” attacks on doctors and nursing staff and thanked attendees at Tuesday's interrupted lecture for their "civil courage.”

"Many accomplished scientists and doctors had benefitted from Fritz von Weizsäcker's tutelage, wrote medical colleague Michael Geissler in an eulogy published by Die Welt on Wednesday.

"With great enthusiasm, he accompanied and supported young medical students on their way to becoming doctors," wrote Geissler, himself the son of the late Heiner Geissler, a high-serving veteran of Merkel's Christian Democratic (CDU) party.

Open clinic access to remain

Germany's DKG Hospital Federation on Wednesday said installing access controls like those used at airports would violate the public's wish for open clinics.

Tuesday's attack was an "absolute exception”, said DKG president Gerald Gass, saying staff were trained to spot and deescalate tense situations.

A wise and respected voice An outstanding politician He was born in a palace in Stuttgart and would become both the governor of Berlin and the sixth president of the Federal Republic of Germany. Richard von Weizsäcker, who belonged to the Christian Democratic Union, was known as a moral authority in Germany.

A wise and respected voice Fraught family ties His father, Ernst von Weizsäcker, was a senior figure in Hitler's NSDAP. After the Second World War, he was sentenced to seven years in prison for war crimes. He was convicted for complicity in the deportation of Jews, a sentence that would influence the life of his son, Richard von Weizsäcker.

A wise and respected voice Early political life He married his wife Marianne Weizsäcker, with whom he had four children, in 1953. After studying law, he worked in a number of leading companies in Germany, among them Boehringer Ingelheim. Von Weizsäcker joined the CDU in 1954. Helmut Kohl discovered him early and recommended him for the office of president in 1968 - without success.

A wise and respected voice A respected mayor In 1982, as governor of Berlin, he received - together with then Chancellor Helmut Schmidt - the president of the United States, Ronald Reagan. He was able to push through a number of reforms during his tenure in Berlin, including the creation of an immigration representative.

A wise and respected voice Bridging the divide On September 15, 1983, von Weizsäcker was received by the head of East Germany, Erich Honecker, in East Berlin. This was the first meeting of its kind, and it was an important symbol of reconciliation between East and West Germany. This was one reason why von Weizsäcker was named honorary citizen of the German capital following reunification, in 1990.

A wise and respected voice A respected statesman On July 1, 1984, von Weizsäcker was voted almost unanimously as president of Germany. From then on, he was seen as a high representative of the republic and respected for his humor and the way in which he represented Germany as head of state.

A wise and respected voice Words that live on "May 8, 1945 was a day of liberation." Richard von Weizsäcker made his observation about the end of the Second World War during a commemoration ceremony in 1985. He received both praise and criticism for speaking those words - and went down in history.

A wise and respected voice On the periphery During his tenure as president, the reunification of West and East Germany took place. Helmut Kohl will forever be known as the "Chancellor of Re-Unity," though von Weizsäcker remained on the fringe. He preferred not to overemphasize the convergence of the German two states.

A wise and respected voice Campaign for Europe Even after his tenure, von Weizsäcker remained active on a political level. Before the eventual implementation of the euro in 2001, he could be seen as a campaigner for the European currency, a sign of his desire for a unified Europe - or at least a monetary European Union. Author: Jeanette Seiffert / gb



ipj/rt (dpa, AFP)

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