German police said on Friday five people were injured when a fire broke out at a refugee shelter in the town of Heppenheim in the West German state of Hesse.There was no immediate indication of how the blaze began. Germany, which expects the influx of refugees and migrants to quadruple to about 800,000 this year, has witnessed more than 100 arson attacks on asylum shelters in recent months."One resident who tried to rescue himself by jumping out of a window from the second floor was seriously wounded," police spokeswoman Christiane Kobus said in a statement.Four people were slightly injured by smoke poisoning, she said. More than 60 refugees from countries such as Syria, Iraq, Somalia and Ethiopia were accommodated in the three-story residential building."The fire was extinguished quickly. According to initial findings, the fire emerged behind the entrance door for unknown reasons," Kobus said. Police and state prosecutors had started an investigation into the cause of the fire, she said.