LONDON (AP) _ A brother-in-law of Prince Philip, Queen Elizabeth II's husband, was a high-ranking officer in the Nazi SS, London newspapers said Sunday.

In new reports of links between the elite Nazi unit and members of the royal family, the Sunday Times and the Mail on Sunday identified the officer as Prince Christoph of Hesse, who married Prince Philip's sister Sophie in 1930.

Prince Christoph was killed in an air crash in 1943 after reaching a rank senior to colonel and ''was a close aide of Heinrich Himmler, head of the SS and the Gestapo,'' the Sunday Times said.

The reports followed Tuesday's disclosure by the Daily Mirror that the wife of the queen's first cousin, Prince Michael, is the daughter of the late Baron Gunther von Reibnitz, an SS officer who joined the Nazi party before dictator Adolf Hitler achieved power in 1933.

Buckingham Palace refused to comment on the reports.

The Sunday Times said that Prince Christoph was head of an espionage network during the 1930s that gathered intelligence for the Nazis.

It said the network helped Hitler prepare for the 1939 invasion of Czechoslovakia and to deceive British Prime Minister Neville Chamberlain, who thought he had gained a lasting peace in negotiations with Hitler at Munich the previous year.

There had been speculation earlier the royal family knew about Princess Michael, the former Baroness Marie-Christine von Reibnitz, but suppressed the facts about her father because of their own links with German families who held high office under Hitler.

The baroness had said her father was Austrian. After the Daily Mirror disclosure, she said she had not known he was a member of the SS. The SS ran the death camps in which millions of Jews, Russian prisoners of war, gypsies and other prisoners were put to death.

The royal family's German connections go back to the start of the 18th century when the crown passed from Queen Anne to King George I of Hanover, the nearest Protestant relative.

The Sunday Times said it had interviewed Prince Christoph's son, Prince Rainer of Hesse, a cousin of the British heir to the throne Prince Charles.

Prince Rainer ''confirmed that the Hesse family was close to Hitler and received 'preferential treatment,''' the newspaper said.

Prince Christoph joined the SS in 1933, it added, citing documents in London's Imperial War Museum, which hold SS records that confirmed Baron von Reibnitz's SS membership.

The Sunday Times said: ''Although Prince Philip served in the Royal Navy during the war, others in his family were closely connected with the Nazis. His uncle Duke Charles of Coburg, for example, acted as Hitler's ambassador to Britain before World War II and was a lieutenant general in the SA - the Storm Troopers - and remained a close aide of Hitler until 1945.

''A distant cousin of Prince Christoph, Prince Wilhelm of Hesse, was a captain in the SS Death's Head Corps, which guarded concentration campas ....

''Prince Christoph's elder brother, Prince Philipp, was a friend of (Nazi air force leader) Hermann Goering ... and was responsible for organizing the robbery and confiscation of Europe's art treasures for Hitler's Austrian Museum.''

Prince Rainer, who lives near Kronberg, West Germany, was quoted as telling the Mail on Sunday, ''Our relationship with your royal family has never been damaged by my father's activities during the 1930s and the Second World War.''

The weekly noted that last December, Britain's Prince Philip and Prince Charles attended a 70th birthday party for Princess Sophie.