A POLICE officer called to a fatal road accident in northern New South Wales has discovered his son was one of two teenagers killed in the crash.NSW Police Commissioner Andrew Scipione today described the incident as a tragedy and every officer's worst nightmare. The 17-year-old was killed along with another teenager, also 17, when their Holden Commodore left Pinkett Road, east of Glen Innes, hit a stump and then rammed a tree. An 18-year-old passenger in the backseat survived the crash, which occurred just after midnight (AEST). He remains in a critical condition in Newcastle's John Hunter Hospital. The driver of the car was on his learner plates, police have said. "Neither passenger was qualified to be a supervising driver," a police spokesman said. "The crash happened about 12.30am ... when a Commodore sedan left the road, struck a tree stump and became airborne before it hit a second tree. "The driver, a 17-year-old youth from Red Range, and his front-seat passenger, aged 17 from Glen Innes, died at the scene." The 18-year-old, also from Glen Innes, was first taken to Glen Innes Hospital with severe injuries before being flown to Newcastle for specialist treatment. The father of the dead teenager is understood to be a senior constable based at Glen Innes police station. "This police officer was simply doing his job," Mr Scipione said. "He went to a motor vehicle accident and the tragedy of being confronted with his own son is beyond description. "Our hearts and our prayers go to the family at this terrible time." Police investigators are also speaking with a number of people who were with the three teenagers earlier in the night. Anyone who witnessed the incident or who has information that may help investigators is urged to contact Glen Innes Police on 6732 9799 or Crime Stoppers on 1800 333 000.