By Kim Glovas, Mike DeNardo, and David Spunt

PHILADELPHIA (CBS) — Four students at a Southwest Philadelphia elementary school are being checked out at Children’s Hospital after police say one of them brought a bag of crack cocaine to school.

Authorities says one student, age 13, brought a sandwich bag filled with packets of what police say was crack cocaine into the Mitchell Elementary School, 5500 Kingsessing Avenue.

According to police, the 13-year-old tried to entice an eight-year-old to hold the bag for the day in exchange for $7.00. The  eight-year-old refused, according to investigators, but the 13-year-old pushed the bag into the eight-year-old’s bookbag.

The eight-year-old then showed the sandwich bag to two other eight-year-olds, one of whom sniffed the substance briefly and the other of whom notified a teacher.

Police say the 13-year-old was found with eight packets of crack in his possession, and police found another eight packets of crack cocaine in the school toilet.

Grandparent Valerie Sloane says, “Someone could’ve died from those drugs. That’s crazy. It’s very shocking, terrible.”

Lt. John Walker with Philadelphia Police says, “It could’ve been bad. Crack cocaine is very addictive in nature. This is cocaine, these are young kids.”

As a precaution, four students — including the 13-year-old and three eight-year-olds — were taken to Children’s Hospital of Philadelphia.  All were expected to be okay.

Parent Duane Evans says, “It’s sad drugs are getting into the school and kids actually know what to do with it.”

Parents who arrived to pick up their kids at the end of the day found the school ringed with police cars and news media vehicles.  Some complained that the school had not informed them of the situation and said they would have picked up their kids sooner had they known what was happening at the school.

Superintendent William Hite told Eyewitness News Thursday night an investigation is underway.

“It’s really important for us to find out how this child came into possession of these drugs and how on earth do they end up with a 13-year-old at a school, at an elementary school,” said Hite.

Superintendent Hite tells Eyewitness News the children are okay.