( CNN ) -- The remains of a firefighter killed in the September 11 , 2001 , terror attacks at the World Trade Center have been identified , the New York City Medical Examiner 's office said Friday . Lt. Jeffrey P. Walz , 37 , was identified after authorities retested remains that were recovered in the months following the attack . Of the 2,753 people killed in the attack , more than 1,100 people have not had remains identified , according to Barbara Sampson , acting chief medical examiner . More than 8,200 bone samples and additional samples require DNA testing , according to a report released by Sampson . Walz , who was last seen in the north tower of the World Trade Center , was survived by a wife and a son , according to an obituary in the Staten Island Advance . Crews finish installing World Trade Center spire .
Firefighter Jeffrey Walz was killed in the attack on the World Trade Center . Walz , 37 , was last seen in the north tower . He had been a firefighter for 10 years and worked his way up to captain of Engine Company 12.