A teenager arrested on suspicion of causing an explosion at a Stockholm school that injured a girl may be behind several other neighborhood blasts, police said. The explosion at the Solbacken preschool was the result of a powerful homemade firecracker and a 4-year-old girl\'s hands were injured in the blast, The Local reported Tuesday. \"The girl found the cracker inside the preschool\'s area. It exploded in her hand,\" Lennart Lofgren of the Stockholm police said. She was operated on at a hospital and is expected to make a complete recovery, doctors said. Police said several other blasts around the area involved the same type of homemade firecracker found at the preschool and said the teenager may be responsible. \"We have questioned him but we can\'t disclose too much of what he has said,\" Ville Paloheimo of the local police said. \"We are now working on questioning people around him and gather information about the other explosions.\" The teenager, who reportedly was known previously to the police, could face charges of attempted murder or aggravated assault, The Local reported.