A man who carried out "a vicious and sustained knife attack on a defenceless elderly woman in her home" has been sentenced to life in prison for murder.

The body of Una Crown was found in her home in Wisbech, Cambridgeshire, on January 13, 2013. She had been stabbed four times and her throat had been cut.

Cambridgeshire Police did not treat the death as suspicious until two days later, but neighbour David Newton, 70, who had previously been arrested but later released, was charged last April following a DNA discovery.

Judge Justice Garnham said the perpetrator of the murder should serve at least 21 years in prison.

Crown's body was discovered in the hallway of her home by relatives who had arrived to take her to lunch on Sunday. However, police officers initially treated the death as "unexplained." This meant that police, firefighters, paramedics and undertakers went through the house, and some even touched Crown's body to move things around.

It wasn't until two days later - following a post-mortem examination - that the death was finally ruled suspicious. However, DNA taken from Crown's fingernails at the time of her death was re-tested by forensic scientists 10 years later, leading to Newton being charged.

At the time he had been an odd-job man, living in Magazine Close a few streets away.

After his trial, Newton was found guilty of murder. During the sentencing hearing, defense attorney Claire Matthews, for the prosecution, said Crown had been stabbed with a knife at least 24 centimeters long.

There was no evidence of a sexual assault. Matthews said the evidence suggested Newton was drunk and a "trespasser" at home.

Defense attorney Henry Grunwald said Newton was now "a very different man" than he had been in 2013. "He's not a good man," Grunwald said.

Newton suffered from problems including depression, diabetes and rheumatoid arthritis, and Grunwald added that his client could die in prison.