Additionally, Erik's threats of violence against his psychologist that led to the arrests also earn no pity.
According to the movie, Erik checked with Dr. Oziel to make sure that the doctor/client confidentiality rule was in place before he confessed. Oziel assured him it was. After the confession, Oziel called Lyle and told him he should come to the office, which Lyle did. When he heard about the confession, Lyle and the doctor got into a heated argument during which Lyle threatened to kill him. This was confirmed by a quick Google search.
This argument was overheard by the doctor's secretary who then called the police even after being warned by the doctor not to tell anyone. She was under no confidentiality restrictions.
What wasn't mentioned in the movie was that the brothers had already confessed to Erik's best friend.

