A PAKISTANI NATIVE who a source said is on the FBI's terrorist-watch list kidnapped his girlfriend's baby from an Upper Darby home Sunday and may have killed the 7-month-old and buried his lifeless body along a rural roadside in York, police said. Ummad Rushdi, 30, has been charged with kidnapping and related offenses after he was arrested early yesterday at his home in York. The baby, Hamza Ali, was last seen alive Saturday night and hasn't been found, said Upper Darby Police Superintendent Michael Chitwood. "Our hope is that the child is alive, but the reality of the investigation thus far ... is that the baby is probably dead," Chitwood said. The baby's mother, Zainab Gaal, 20, who was born in Somalia and raised in Yemen, began dating Rushdi just three or four weeks ago, police said. Gaal and her son were already living with Rushdi and his brother at their home in York, police said. Authorities didn't immediately know when Gaal came to the United States, and did not know the whereabouts or identity of her child's father. Last week, the three adults and baby Hamza traveled to Upper Darby to stay with Rushdi's parents at their well-kept stone rowhouse on Chestnut Street near Powell Lane, police said. Several days before the kidnapping, Rushdi allegedly hurt the baby's shoulder, Chitwood said. Gaal wanted to take Hamza to the hospital because she feared his shoulder may have been broken, but Rushdi and his parents wanted to "self-medicate" the boy, Chitwood said. On Sunday morning, Gaal and Rushdi's family awoke to find Rushdi and Hamza missing, police said. Rushdi's brother began to relay calls between Rushdi and Gaal, saying that the baby was fine and that Rushdi would return him to Upper Darby, Chitwood said. In one conversation, Rushdi's brother allegedly told Gaal that Rushdi was taking the baby to live with Gaal's parents in Maine because the boy was "interfering" with the couple's relationship, Chitwood said. Several of Rushdi's family members went to look for him and the baby in York, but Gaal remained in Upper Darby, police said. Finally on Tuesday, Rushdi's brother told Gaal that Rushdi had awakened before everyone in the house in Upper Darby on Sunday and went into a room by himself with the baby, where he had "some type of interaction" that led to the child's death. Gaal called police about 8:30 p.m. that night. "Rushdi did not want to share with the mother that the baby had died, so he drove the baby out of that location," Chitwood said. Police believe that Rushdi drove with the dead baby in his car nearly 100 miles to a rural area off Route 30 near York, where his car was found abandoned by police. "We believe that Rushdi then buried the child somewhere up there," Chitwood said. Rushdi was arrested in York about 2:30 a.m. and was taken to Upper Darby to be arraigned on charges of kidnapping, reckless endangerment and related offenses. According to a law-enforcement source, Rushdi is on the FBI's terrorist-watch and no-fly lists. "He was planning to go to Canada or Mexico, because he knew he couldn't fly," the source said. Authorities found a knife, handcuffs and $800 in cash on Rushdi when he was arrested, police said. Philadelphia FBI spokeswoman Carrie Adamowski could not confirm or deny whether anyone was on the terrorist-watch list.