None of the four officers was present during the explosion of the roadside bomb and the subsequent civilian killings by marines.

The subsequent killings of alleged informers occurred while the officers were being held and interrogated.

Neither forensics tests nor other evidence in the subsequent killings have established any further pattern, the police said.

Prosecutors around the nation say the intimidation of witnesses, and their subsequent killing, is on the rise, especially in gang-related crimes.

The lot fell to the man who had suggested the scheme and he consented to his subsequent killing.

He scanned the details of the escape and the subsequent killing of the female motorist whose car was stolen.

His subsequent killing caused a national uproar.

Some published reports have linked subsequent killings to Mr. Scarpa's death.

"The whole focus has changed because of the subsequent killings," he said, declining to comment further.