ROCHESTER, N.Y. (AP) — Two upstate New York firefighters remain hospitalized in guarded condition Tuesday, a day after being shot in a hail of bullets that killed two other firefighters responding to a house fire that investigators say appears to have been set as a trap.

Firefighters Joseph Hofstetter and Theodore Scardino are recovering at a hospital in Rochester, New York.

They were among four firefighters who responded to the blaze in the suburban Rochester town of Webster Monday morning. Authorities say William Spengler set a house and car ablaze and then opened fire when the firefighters showed up. He later exchanged bullets with a police officer before killing himself.

Spengler's sister is missing. The 62-year-old was released from prison in 1998 after serving 17 years for killing his grandmother.