A fire in York City on Friday night that displaced five people and killed one dog was caused by arson, said York City Fire Chief David Michaels.

The fire was contained to the front room of the third floor apartment of 39 South Hartley St., he said. The fire caused $15,000 in damage, he said.

The Red Cross said in a Saturday morning press release that volunteers were helping three adults who had been displaced by the fire on the first block of South Hartley Street.

The investigation into how the fire started is ongoing, he said.