"If we made no attempt to apprehend him, that's inexcusable," Johnson said. "It's very disturbing. But this still doesn't mean that it would have prevented Officer Cassidy from being shot. "
In another development, police confirmed they had questioned Lewis shortly after the killing but released him because they had been focused on another suspect.
On Oct. 20, an employee of Oasis Pizza identified Lewis - a regular customer - as the gunman who had held up the eatery that night.
"If they had caught the guy," the murder of Cassidy "would never have happened," the 21-year-old worker, who identified herself only as Melendez, said last night. "They left me with the impression that they knew where he was at, but they never caught him. "
Police would not identify the assigned detective or her supervisor, citing the internal investigation. Those familiar with the case say the detective, an experienced veteran, is distraught over Cassidy 's death.
Six days into a massive manhunt, Lewis, 21, an Olney High School dropout, was captured in Miami and confessed. He has been brought back here and is facing murder charges.
Internal Affairs investigators are reviewing exactly what happened in the weeks before the fatal robbery and whether Lewis should have been off the streets.
Yesterday, after learning of the pizza-shop robbery, Johnson consulted top commanders, including Chief of Detectives Keith Sadler and Deputy Commissioner Patricia Fox, before ordering the Internal Affairs probe.
Johnson said no disciplinary action, if warranted, would be taken until the investigation was completed. The detective did act quickly to identify a suspect, he said. She had discretion on how to proceed, he said, but it remains unclear exactly what she did.
Said Sadler: "At that point, the detectives are obligated to take the case forward. Something was not done. "
