A Hong Kong (search) jury Thursday convicted an American of murdering her wealthy investment banker husband by drugging him with a milkshake laced with sedatives and beating him to death in the couple's luxury apartment.

Nancy Kissel (search) was expressionless as the seven-member jury returned the verdict in the November 2003 death of her husband, Robert, of New York.

The verdict came after dozens of witnesses spent nearly three months testifying in one of Hong Kong's longest and most high-profile murder trials. The often sensational testimony about abusive sex, adultery, cocaine and money gave the public a rare peek inside the private life of a wealthy foreign couple.

The prosecution portrayed the 41-year-old as a cold-blooded killer who murdered her husband — a top investment banker at Merrill Lynch (search) — as he prepared to divorce her and seek custody of the couple's three children.

Robert Kissel, 40, was furious that his wife had an affair with a repairman who lived in a trailer park near the couple's vacation home in Vermont, the prosecution said.

But the defense argued that the husband was an abusive workaholic who snorted cocaine and often forcefully sodomized his wife, driving her to seek comfort from a lover. The defense said Nancy Kissel, who was born in Adrian, Mich., and also lived in Minneapolis, killed her husband in self-defense as he was attacking her with a baseball bat during an argument.

The prosecution said she tried to cover up the killing by rolling up her husband's body in a rug and having it hauled away to a storage locker rented by the couple.