Security systems at Kaiser apparently detected unauthorized access to patient information:

The computer breaches at the Bellflower hospital were discovered about 10 days ago and reported to state authorities and to Suleman, said Kaiser spokesman Jim Anderson. He said that 15 employees were fired and eight were disciplined. The employees “ran the gamut of medical staff,” he said. The privacy violations occurred despite the hospital’s stepped-up efforts to shield Suleman’s records from employees who had no medical reason for accessing them, Anderson said.

Gamut is an interesting way of saying that everyone was doing it. Note that the “stepped-up” efforts might have worked to shield against additional abuse, so the 23 staff caught might be seen as a lesser number than what might have happened. UCLA had over 100 staff implicated in their breach investigations. This once again emphasizes the importance of a detective strategy to enhance preventive measures.