Hamburg, March 5 (DPA) A boarding school in Germany which was once headed by Georg Ratzinger, the brother of Pope Benedict XVI, says it is checking out a claim that a teacher committed sex abuse in the early 1960s.

The Regensburger Domspatzen School, which educates the children who sing in one of Germany's top boys' choirs, said it was shocked to discover a newspaper clipping from the 1950s showing that a man who directed the boarding department was convicted of sex abuse.

The school is under the control of the director of music at Regensburg Cathedral in Germany. The priest who held that post till 1963 was Theobald Schrems, followed by Georg Ratzinger from 1964 to 1994.

Ratzinger, 86, told Bavarian radio in Regensburg Friday he was not aware of any cases of sex abuse at the school and declined further comment.

In a letter to former pupils published on its website, the cathedral director of music, Roland Buechner, said the school was trying to make contact with a man who has told German newspapers he suffered sexual abuse while he was a pupil at the start of the 1960s.

The Catholic Church has come under heavy attack in Germany in recent weeks over allegations that senior officials failed to keep a small number of convicted paedophiles away from children right up to the 1980s.

Nationwide, about 150 people have contacted church-appointed lawyers, describing how they were abused at various church schools. Almost all the cases occurred too long ago to be prosecuted now.

The German bishops are now reviewing whether their 2002 guideline on sex abuse is strong enough. It says that bishops do not need to report borderline cases to police, but should only suggest to offenders that they turn themselves in.