BOSTON – A lawyer for a German man who pretended to be a member of the Rockefeller family argued Friday that his client’s conviction for kidnapping his daughter should be thrown out because his trial was marred by the “evisceration” of his insanity defense.

Christian Karl Gerhartsreiter, who used the name Clark Rockefeller as one of his aliases after moving to the U.S. in the 1970s, was convicted in 2009 of kidnapping his 7-year-old daughter during a supervised visit. He also was convicted of assault and battery with a dangerous weapon for instructing his hired driver to speed away after he snatched his daughter, injuring a social worker.

During closing arguments at his trial, the prosecutor noted the defendant’s history of using aliases and urged jurors not to let his insanity claim be “the culminating manipulation in a lifetime of lies.”

The statement denigrated the insanity claim as an illegitimate defense, Gerhartsreiter’s lawyer, Jeffrey Denner, argued before the Massachusetts Appeals Court on Friday. He also argued that the state’s expert witness was not qualified to testify.

The three-judge panel did not indicate when it would rule.