Candles lit for an evening meal on a three-season porch and left unattended started the fire at a New Ulm, Minn., bed and breakfast that killed six people early this month, according to state investigators' findings released Monday.

The report said the fire at the Bohemian Bed and Breakfast has been ruled accidental.

The determinations were made by the New Ulm fire and police departments and the state fire marshal's office.

"Based on witness statements and fire patterns ... the fire built energy before breaking into the home through the picture windows of the TV and the grand staircase area," according to a report by state fire marshal investigator Denise DeMars.

Those killed in the July 2 fire were Roberta McCrea, 48, owner of the Bohemian; Abby Wood, 15, and Savannah McCrea, 3, her daughters; and lodgers Andrew Uhing, 67, of Hartington, Neb., and Joseph Bergman, 62, and Dian Bergman, 59, both of Centuria, Wis.

Five died of carbon monoxide poisoning, and Joseph Bergman died from burns, according to the Ramsey County medical examiner.

Three others escaped: Charles Zangl, 53, McCrea's fiancé and Savannah's father; and Diane Frye, 54, and Charles Frye, 58, of Plymouth.

Penny Purtzer, whose aunt and uncle sold the home to McCrea in 2002, said that the knowledge of the fire's cause gives her little comfort: "We all knew that it wouldn't make us feel any better when we learned the cause. ... Bobbi and the girls are gone."

Investigators estimated the cost of the fire damage to the Victorian-era house at $900,000.

According to the report:

Roberta McCrea lit at least two candles for the dinner on the porch's north side. One was on the table and the other in a holder similar in design to a floor lamp. At the meal were McCrea, Zangl and Savannah, and visitors Ruth and David Mecklenburg, of Sleepy Eye, Minn., who are Zangl's sister and her husband.

Zangl told investigators that he couldn't recall if anyone extinguished the candles. Zangl said he fell asleep on a couch in the TV room.

Sometime before 2 a.m., passerby Rodney Zimmer ran through the 2 1/2-story wood-frame house screaming, "There's a fire!" the report said.

Zangle said he thought he was asleep when Zimmer yelled that the house was on fire. Zangle said he saw flames on the porch and tried to go up the stairs near the kitchen, but was driven back by heavy smoke, the report said. Zangl said he called for his fiancé but didn't get an answer.

Firefighters found McCrea's body on the first floor near the kitchen and dining room, the report said. The other victims were found on the second floor of the bed and breakfast.

The blaze burned everything available on the porch and left it severely charred.

Three guests told police that they heard smoke detectors sounding. The detectors could also be heard during one of the two 911 calls.

Elwood Zabel, the city's fire marshal, said he had not conducted an annual fire inspection of the main house in December 2010 because he was told it was not going to be used for lodgers.

City records show the owner had not applied for a license to use the main house for guests in 2011, although she had done so and been granted approval in previous years.

However, the Bohemian continued to advertise the guest rooms on public websites.

Star Tribune staff writers Randy Furst and Nicole Norfleet contributed to this report. Paul Walsh • 612-673-4482