Hundreds of police officers, two dozen religious leaders, and the family of slain Philadelphia police Sgt. Steven Liczbinski observed a minute of silence for "peace and healing in our community" today at the steps of the Roman Catholic cathedral.

The solemn silence followed an hour-long interfaith prayer service inside the cathedral "for peace and healing in our community."

The service also marked the 30 days that have passed since Sgt. Liczbinski's fatal shooting.

The most moving event of yesterday's hour-long service came early, when Mayor Michael Nutter and Police Commissioner Charles H. Ramsey presented Liczbinski's widow and three children with the American flag that flew half-mast above City Hall. "When you look at it, know the city has stood with you and will stand with you as you go forward," he told them.

Sponsored by the Religious Leaders' Council of Greater Philadelphia and the Mayor's office of faith-based initiatives, the prayer service brought Jewish, Protestant, Catholic, Orthodox, Muslim and Buddhist leaders from around the region to the altar of the Cathedral Basilica of Saints Peter and Paul.

"Only by changing hearts can we live in true, lasting peace," Cardinal Justin Rigali told the gathering, which drew about 1,000.

Just before the close of the service, Nutter formally signed a pledge for peace that he urged all Philadelphians to take.

It includes a commitment to "eliminate the causes of hatred, to honor the dignity of all people, to lay down our weapons, and to find non-violent solutions when tempted to hurt another."