A Manhattan judge must decide whether to allow the videotaped confession of a man charged with murder in the death of a 1979 missing boy.

The hearing begins Monday and is expected to last several weeks.

A lawyer for Pedro Hernandez says his confession was wrongly obtained. He says in court papers that his client lacks the mental ability to understand his rights. Prosecutors have argued the confession was legally obtained.

Etan Patz (AY'-tahn payts) disappeared on May 25, 1979 walking to school. His body has never been found. Hernandez was charged with the crime two years ago after he confessed, but pleaded not guilty. His attorney Harvey Fishbein says the confession is false.

The hearing will determine whether the confession is admissible in court, not whether it's true.