By Al Novack and Suzanne Monaghan

FALLS TOWNSHIP, Pa. (CBS) — Falls Township Police say four people crashed an apparent underage drinking party, and robbed the party-goers.

The incident happened Thursday night inside a home along Hedgerow Drive, where police say a group of 10 people, all between the ages of 18-20 years old, were having a party and allegedly consuming alcohol while the homeowners were out of town.

Police say four people showed up at the party, and robbed the party-goers of their wallets and cell phones.

At one point, police say a party-goer was struck in the face with an unknown object and suffered a facial injury.

Then, one of the robbers, who was armed with a handgun, became involved in a struggle, but no shots were apparently fired. Investigators says they found no shell casings at the scene.

So far, there is no word of any arrests.