The upstate New York firefighters wounded by a gunman as they responded to a blaze are on the mend and thankful for the outpouring of support.

Volunteer firefighters Joseph Hofstetter and Theodore Scardino said in a statement released by Strong Memorial Hospital that they are "humbled and overwhelmed."

The pair were being upgraded to satisfactory condition on Wednesday at Rochester's Strong Memorial Hospital and were "convalescing and doing as well as I would expect at this stage," Dr. Nicole Stassen told CNN News.

"Mr. Scardino and Mr. Hofstetter are both receiving supportive care and are making small steps on their long road ahead," she said.

Police say William Spengler Jr. set his house ablaze Monday and then opened fire on responders, killing two. Spengler then killed himself as seven surrounding houses burned down.

Lt. Michael Chiapperini, of both the Webster police and volunteer fire departments, has been identified as one of the firefighters killed Monday. (Webster Police Department)

Hofstetter was hit in the pelvis and Scardino was hit in the shoulder and knee. Surgeon Nicole Stassen says they're doing well and were being upgraded to satisfactory condition Wednesday. The firefighters ask that acts of kindness be directed to others, including those who lost homes in the blaze.

The firefighters also said their "thoughts and prayers" were with the families of colleagues Michael Chiapperini and Tomasz Kaczowka, who were killed in the ambush. Funerals are set for the next few days for Chiapperini and Kaczowka.

Chiapperini, 43, was also the Webster Police Department's public information officer, and 19-year-old Tomasz Kaczowka, worked as an emergency dispatcher.

Chiapperini had nearly 20 years in the department, and Police Chief Gerald Pickering called Kaczowka a "tremendous young man."

Positioned like a sniper

Authorities said Spengler set a car on fire and touched off an "inferno" in his Webster home on a strip of land along the Lake Ontario shore, took up a sniper's position and opened fire on the first firefighters to arrive at about 5:30 a.m. on Christmas Eve.

Spengler, 62, traded rifle fire with a Webster police officer who had accompanied the firefighters and then killed himself with a gunshot to the head.

Investigators found a rambling, two- to three-page typed letter laying out Spengler's intention to destroy his neighborhood and "do what I like doing best, killing people."

William Spengler served 17 years in prison after the beating death of his 92-year-old grandmother in 1980, after pleading guilty to a reduced charge of manslaughter. (Monroe County Sheriff's Office/Associated Press)

They believe remains found in the burned home are those of his sister, Cheryl Spengler, but that hadn't been confirmed, and it was unknown how she died. The Spengler siblings had lived in the home with their mother, Arline Spengler, who died in October.

There also was no word from authorities about how William Spengler, who served time for his grandmother's beating death, got three guns found with his body: a military-style Bushmaster .223-caliber semiautomatic rifle, a 12-gauge shotgun and a .38-caliber revolver.

The rifle, which had a combat-style flash suppressor, is the same make and caliber as one used by a gunman to massacre 20 children and six women at a Newtown, Conn., elementary school earlier this month.

Federal authorities confirmed Wednesday they had traced the sale of the weapons, but they didn't release details.

Spengler spent 17 years in prison for beating his paternal grandmother to death with a hammer in 1980. He had been released from parole on the manslaughter conviction in 2006, and authorities said they had had no encounters with him since.

Pickering said investigators believe Spengler used the rifle to attack the firefighters because of the distance involved. He said police may never know Spengler's motive.

Chiapperini, who also was a police lieutenant, was driving a pumper with Scardino on board when bullets blasted the windshield. He and Kaczowka died at the scene. Hofstetter was hit in the pelvis, and Scardino was hit in the shoulder and knee.

A passing off-duty officer from the town of Greece was treated for shrapnel wounds from gunfire that hit his car.

Hearses carrying the coffins of Chiapperini and Kaczowka were escorted to West Webster Fire Station 1 on Wednesday, where they were met by emergency vehicles with their lights flashing in salute.

A funeral for Chiapperini is scheduled for Sunday at the school, with burial in West Webster Cemetery. A funeral Mass for Kaczowka will be held Monday in Rochester at St. Stanislaus Church.