DOVER, N.H. – A teen held in connection with the stabbing death of his pregnant ex-girlfriend now faces first-degree murder charges.

The New Hampshire Attorney General’s Office decided to upgrade charges against 19-year-old Anthony O’Leary from second degree to first degree murder after “careful review of the evidence,” Assistant Attorney General David Ruoff said Tuesday.

O’Leary faces life in prison without parole if found guilty of first-degree murder. He would have been eligible for parole if convicted of second-degree murder.

The body of Treasure Genaw, 17, was found stabbed in woods near South Berwick, Maine, early on the morning of June 9, days before her graduation from Noble High School and two weeks before her 18th birthday.

Genaw was three months pregnant and friends said O’Leary, Genaw’s ex-boyfriend, was the father.

O’Leary was arrested in Massachusetts after state police tried to stop his speeding car southbound on Interstate 95. Troopers found blood in his car after the chase ended.

Police say O’Leary killed Genaw in Somersworth, N.H., and dumped her body in Maine.

O’Leary was being held without bail at Strafford County Jail in Dover, N.H. He is scheduled to be arraigned in August.