unaccounted for

シアトル郊外のバーでの発砲事件の後，ニューヨーク州でも火事の現場に駆けつけた消防士４人が撃たれ、２人が死亡、２人が負傷する発砲事件がありました。クリスマス休暇だというのに...。

unaccounted forは以前にも取り上げましたが，ここではどのような意味でしょうか。Minnesotaくん，どうぞ。（UG）

Gunman ambushes, kills two firefighters at New York blaze

(CNN) -- A man convicted of killing his grandmother decades ago allegedly ambushed firefighters on Monday, fatally shooting two of them as they arrived to battle a blaze in upstate New York, police said.

Two other firefighters were wounded in the attack in the Rochester-area town of Webster. Investigators believe the suspect, William Spengler, 62, deliberately lured them to a house fire, Webster Police Chief Gerald Pickering said.

Spengler was convicted in 1981 of first-degree manslaughter in the death of his grandmother and had been released on supervised parole, Pickering said.

"It is possible that a sister of Mr. Spengler is unaccounted for," Pickering said, adding that her last known address was at the residence where the shooting occurred.

For more than three hours on Monday, the threat of gunfire stopped firefighters from battling the blaze and forced police SWAT teams to evacuate 33 people in the neighborhood of small waterfront homes.

Seven houses were destroyed in the fire and it was unclear if everyone had been evacuated safely.

"I'm hoping that everyone was able to escape from the inferno," Pickering said. "Those houses were close together."

http://edition.cnn.com/2012/12/24/us/new-york-firefighters-shooting/index.html?hpt=hp_t3