OAKLAND -- A troubled nephew was arrested Friday for the brutal early morning murder of an elderly woman in her Oakland home and an arson fire set to allegedly cover-up the crime.

The badly burned body of Amanda Pierre, 89, was discovered shortly after firefighters began battling the one-alarm house fire on 24th St. in Oakland. The suspicious fire -- now called an arson -- charred the inside of the home before it was brought under control within 20 minutes.

Police arrived at the scene and detained the woman's nephew on unrelated charges and were questioning him about the murder and fire. Shortly thereafter, police officers recovered a bloody knife and smoke alarm from a nearby storm drain.

Investigators told KTVU they then arrested the nephew -- Alan Thomas -- in connection with the crime.

"It's mind-boggling," Inez Strane, the niece of the dead woman, told KTVU. "Now it is more than devastating. I thought he (the nephew) had gotten it back together…I'm praying it's (being the killer) not him, but if it is, he needs to spend the rest of his life in jail."

Family members said Thomas -- who lived down the street in a VW bug -- had recently reconciled with the aunt after several troubling months. He had lived with his aunt for a short time but a suspicious fire at the home had led to a restraining order against him and an estrangement between the two.

Strane described her aunt as a loving person.

"My aunt was everything," she said. "My aunt was a loving, kind individual. She was a Christian lady who loved the Lord and loved everyone."

The incident remained under investigation.