GASTON COUNTY, N.C. -- If you couldn’t see the regret in his face, you could hear it in the voice of Frank Winkles as he talked about the fire that killed his pregnant neighbor.

"Sadness that I couldn't do any more," he said.

Wednesday morning, 31-year-old Lucy Johnson's body was found in her charred house on Hidden Meadow Court just east of Gastonia. Police said the house was set on fire.

Wrinkles watched investigators literally excavate the ashes next door. His melancholy eyes often darted away from the Eyewitness News camera to catch a glimpse of the agents and police nearby.

"It's sad. It's really sad to me," he said. "I will miss Lucy.”

Around 3 a.m. Wednesday, Winkles’ wife woke him and told him there was a fire next door.

"I went straight out the door and run over there," he said. "I was yelling out as loud as I could, trying to stir somebody up or something."

Winkles said he tried to open doors but they were locked. He ran to the back door.

"The flames, it just seems like it had an accelerant. It just burst out," he said.

He shook his head as said, "I wish there was something else I could have done, but that was about it."

Police said an accelerant was indeed used to start the fire. Johnson was a nurse and mother of two, who was home alone at the time of the fire. Her 7-year-old girl and 6-month-old boy were staying with their respective fathers. She was pregnant and engaged to marry again.

Thursday, State Bureau of Investigation agents combed the ground with metal detectors and police sifted through the ashes looking for clues. Capt. Calvin Shaw of the Gaston County Police Department said, "We are closer than where we were yesterday, and know more of the people we need to talk to."

He would not say who those people are. Johnson was in a heated custody battle with the father of her young son. In an order of protection filed in September, she wrote that he threatened to cut her with a kitchen knife. She also had an order of protection on her ex-husband. She wrote that he made threats to burn her house down.

In the past three years, there were 10 calls to 911 to report domestic disturbances at Johnson’s home.

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