A black man has been arrested after he tried to saw a cast off his son's hand and severely cut the teenager, according to a Coral Springs police affidavit

Lawrence Roberts, 33, has been arrested and charged with aggravated child abuse, a first-degree felony, punishable by up to 30 years in prison. Police said that his 15-year-old son needed emergency surgery. According to the affidavit, Roberts arrived at the home where the son lives and then retrieved a 10-inch circular saw, usually used to cut wood, from his Chevrolet Silverado and tried to cut the purple cast off his son's right hand, the affidavit said. "The defendant cut off the top of the victim's right thumb, [and] the middle of the victim's right index finger was almost cut entirely off," the affidavit said. Roberts' son, according to the affidavit, also received a 3-inch-long cut on his right hand, between his thumb and index finger. Rescuers took the teenager to Coral Springs Medical Center. He was later taken to Broward General Medical Center in Fort Lauderdale for emergency surgery to repair his thumb. His cast was removed by medical personnel at the hospital, said police spokesman Sgt. Dave Kirkland. Roberts provided a statement to investigators saying that his son's hand was cut while he tried to remove the cast with the circular saw. He did not explain why he used the saw or why he tried to remove the cast, Kirkland said. Roberts was released on $7,500 bond.