A 77-year-old man was charged Wednesday with murder and other counts in the fatal shooting of a fire captain after firefighters responded to a blaze at a senior housing complex in Long Beach, authorities announced.

Thomas Man Kim is facing one count of murder, one count of attempted murder of a firefighter, two counts of attempted murder and one count each of arson of an inhabited structure and explosion with intent to murder, the Los Angeles County District Attorney’s Office said in a statement.

Prosecutors allege Kim was feuding with a female neighbor who lived above him, and set off an explosive device inside his apartment at the 11-story Covenant Manor senior living facility with the intent to kill her early Monday.

Kim left a note  leading investigators to believe the situation was the result of a “murder-suicide attempt,” police said Wednesday.

After setting off the explosive device in his apartment, Kim allegedly sat at the opposite end of the hallway from his apartment and opened fire when Long Beach Fire Captain Dave Rosa, 45, made his way down the hall, the DA’s office said in the statement.

Rosa, a 17-year veteran of the Fire Department who served as captain for the past 6 1/2 years, died Monday from his injuries. Firefighter Ernesto Torres, 35, and another man who lived in the building were also shot but expected to survive.

An official donation site in honor of Rosa has been set up on the Friends of Long Beach Firefighters website.

At a Monday afternoon news conference, Long Beach police Chief Robert Luna had said investigators were looking into whether the fire was set intentionally to lure first responders, and the Associated Press reported on that Tuesday.

“Preliminary evidence and witness statements” indicated that Kim set the fire with the purpose of bringing firefighters to the building, Luna said Monday.

On Wednesday, the Police Department issued a statement on the expected charges against Kim, referring to “multiple erroneous news reports indicating that Long Beach firefighters were lured to suspect Kim’s residence in order to shoot them” and saying the department was not the source of those reports.

The statement concluded:

After multiple interviews and evaluation of the evidence, the preliminary investigation has led investigators to believe the fire was not set to draw first responders to the location to ambush them, but was a result of a dispute between the suspect and a neighbor. Additionally, a note drafted by the suspect and recovered at the scene leads investigators to believe this was a murder/suicide attempt. A motive for the shooting remains under investigation.

Kim was expected to be arraigned Wednesday afternoon.

If convicted as charged, he faces the death penalty or life in state prison without the possibility of parole.

The decision on whether he will face capital punishment will be made at a later date.