The Gaza-based Palestinian Center for Human Rights says it fears Ibrahim Aaraj might have been tortured while in custody at the Nusseirat refugee camp in the central Gaza Strip.

Center staff said Monday that they saw a fracture on the top of his head and bruises on his forehead, face, back and limbs.

Aaraj's brother, Mohammed, told The Associated Press that his brother was arrested on Thursday by narcotics squad officers. Gaza's Islamic militant Hamas rulers take a harsh view of drug offenses.

Hamas police say an investigation is under way.