An American found guilty of murdering her investment banker husband after a sensational trial that featured lurid testimony about drugs, wealth and sexual abuse has filed an appeal, an attorney said Thursday.

Nancy Kissel (search) was sentenced to life in prison on Sept. 1 for the killing of her husband, Robert, in what became known as the "Milkshake Murder" (search).

Kissel, 41, was found guilty of lacing her husband's milkshake with sedatives before bashing his head with a metal ornament at the couple's Hong Kong luxury apartment.

Her attorney, Simon Clarke, said the appeal was filed Wednesday but declined to discuss the grounds for the appeal.

"She is likely to have a hearing date probably in the middle of next year," Clarke said.

During the three-month trial, the prosecution said Nancy Kissel had an affair with a repairman who worked on the couple's vacation home in Vermont.

Her husband discovered the affair and had planned to seek a divorce and custody of their three children just before she killed him in November 2003, the prosecution said.

Kissel was alleged to have subdued her husband — a wealthy investment banker at Merrill Lynch — with a milkshake laced with the date-rape drug Rohypnol (search). She rolled the body up in a rug and placed it in a storage locker the couple rented at their luxury apartment complex, the prosecution said.

Kissel said she killed her husband in self-defense after he attacked her with a baseball bat during an argument. She said her husband snorted cocaine, had a violent temper and frequently subjected her to abusive sex.