A fire investigator on Wednesday blamed a faulty kitchen recessed light fixture that short-circuited for a Lewiston fire late Tuesday.

By Wednesday afternoon, an investigation into the cause of a fire at an Auburn home around the same time was ongoing.

The blaze likely smoldered for "quite some time" in the suspended ceiling in the kitchen at the rear of the house at 110 Spring St., said Paul Ouellette, fire investigator and fire prevention officer at Lewiston Fire Department.

Nobody was in the home when the fire erupted, he said. It was called in shortly before 11 p.m.

Ouellette said the interior of the house sustained more than $100,000 damage. It was insured, he said.

"She had a good head start on us," he said of the blaze.

Ouellette said the home's owner, Allison McLean, had a rabbit, which she had just started leaving outside.

"Thank God, because it wouldn't have been so lucky," Ouellette said. McLean's son, Connor, 9, was staying at McLean's sister's house. McLean, who works the night shift, had left the home a little more than an hour earlier.

The home had a working smoke alarm on the second floor, but none on the first floor, Ouellette said.

He said he called in the city's electrical inspector, Gerry Caron, to help determine the cause.

On the other side of the river, fire investigators were still at work Wednesday afternoon in an effort to determine the cause of a fire at a home at 39 Paul St.

Auburn Fire Department Fire Prevention Officer David O'Connell said he and state fire investigators hadn't determined what caused the blaze that heavily damaged a rear porch, kitchen and second floor at the single-family home.

He said the origin of the fire appears to have been somewhere at the rear of the building on the porch.

Neither he nor investigators from the Office of the Maine State Fire Marshal have ruled whether the fire was suspicious. He said he expected to have more information about the fire's cause and origins Thursday.

Bonnie Desjardins said she had "no clue" what might have started the fire at her house.

O'Connell said the only fire-related injuries reported were two firefighters who went to an area hospital where they were evaluated and released.

Desjardins and her husband, Richard, escaped the fire uninjured with two of their three dogs, but were looking for the third they hoped made it into the backyard. The couple was home at about 10:30 p.m. when they smelled smoke and noticed flames on their back porch.

Desjardins said there were no flames in the main house until her husband opened the back door to see what was going on outside.

"It went from catching the corner of my eye to, 'Oh my God, it's a house fire,'" said neighbor Melissa Shea, who called in the blaze at about the same time as the Desjardins.

Shea said at first she and her husband thought the fire was in the brush and woods behind the houses on Paul Street.

Battalion Chief Scott Hunter said the blaze was knocked down quickly, aside from the back deck of the house. Firefighters from Auburn and Lewiston were still battling the rear of the first house fire when a second broke out on Spring Street in Lewiston.

Ouellette said it was rare to have two fires in the Twin Cities on the same night within such a short time.

Both families were staying with relatives early Wednesday.

Firefighters from Auburn and Lewiston were assisted by departments from throughout the region, including Mechanic Falls, Minot, Sabattus, Lisbon and Greene.