Man's best friend played a dual role at Beechwood Elementary School in Beechview Friday morning, sniffing for explosives but taking time to act as a pacifier for the children.

The school has been on alert since about 2 p.m. Thursday, when a homemade explosive device was thrown into the school parking lot from a passing car.

School was recessed about a half-hour early and the Pittsburgh police bomb squad safely detonated the device later.

The device had wires poking from it and contained an unidentified liquid, police said.

Attendance at the school was down more than usual this morning, said Ebony Pugh, a spokeswoman for the school district.

Some of the students who showed up were happily distracted by the police dog, petting it during pauses in its work, she said.

Students were advised that their teachers were ready to talk with them about any lingering fears. Counselors also were available.