Webster, NY (WIBX) - Police in western New York are releasing fresh details about a shooting that left two firefighters dead in the Rochester suburb of Webster on Monday.

Webster Police Chief Gerald Pickering says investigators found a two-to-three-page typewritten note from 62-year-old William Spengler.

In the note, he said he wanted to do what he does best, killing people.

Pickering says Spengler used a Bushmaster semi-automatic rifle.

That's the same weapon allegedly used by Adam Lanza in the Newtown, Connecticut school massacre earlier this month.

The rifle was one of three weapons recovered at the Webster crime scene.

Pickering says it remains unknown where Spengler, a convicted felon, got the guns.