* Former Credit Suisse banker apologises in court
* Prosecution seeks nine-year jail term
By John O'Donnell
MUNICH, Germany, March 9 A former Swiss investment banker admitted in court on Monday that he seduced and blackmailed Germany's wealthiest woman, heiress to the BMW car empire, with secret films of their hotel trysts.
Helg Sgarbi admitted seducing heiress Susanne Klatten and three other wealthy women and persuading them to pay him almost 10 million euros ($12.64 million) with various tales, including one that he had fallen foul of the Italian mafia.
"I regret what I did," Sgarbi, 44, told the Munich court, with little emotion. "I apologise to the women involved."
Klatten, a member of the Quandt family -- the leading shareholders in carmaker BMW -- went public last year with the story of how her lover filmed their secret meetings and later demanded 49 million euros not to reveal them.
The 46-year-old married mother-of-three had first met Sgarbi at a health centre, state prosecutors told a crowded court.
Posing as a special envoy for war zones, Sgarbi won over Klatten after sending her text messages and phoning her with declarations of his love.
She later handed him a cardboard box containing 7 million euros in 500 euro notes, believing he had paralysed a child in a traffic accident in America and needed the money to pay compensation to avoid being jailed.
Sgarbi then demanded 49 million euros, threatening to send photos and tapes of their hotel-room rendezvous to colleagues, family and the press. His admission means Klatten may not have to appear in court.
Leafing through the defendant's curriculum vitae, judge Gilbert Wolf read from a glowing job reference from investment bank Credit Suisse, describing Sgarbi's role there as a specialist in mergers and acquisitions.
State prosecutor Thomas Steinkrauss-Koch told the court he would seek a nine-year prison term.
"Where is the money? Where are the tapes? And who are the accomplices?" he asked the defendant. Klatten's wealth is estimated by Forbes magazine at almost $10 billion, making her the 68th richest person in the world.
She owns just over half of the chemical company Altana as well as 12.5 percent of BMW.
Newspapers had reported that Sgarbi had sought to justify his actions as revenge for his Jewish grandfather's forced labour in Quandt family factories during the war. But no mention was made of this claim on Monday.
The Quandt dynasty had close ties to the Nazi party and built its fortune supplying German army and railway worker uniforms. The first wife of Klatten's grandfather went on to marry Nazi propaganda chief Joseph Goebbels.
(Editing by Mark Trevelyan)