A man pleaded not guilty to murder in a San Diego County court Friday over the death of an elderly neighbor and friend who was bludgeoned to death in her bed.

Gary Allen Thomas, 63, was believed to have been a "trusted friend" of the victim -- 94-year-old Mary Jean Eskridge -- whom he had accompanied to numerous outings, including church services and dance socials, The San Diego Union-Tribune reported.

Both lived in the Ramona Terrace Mobile Estates mobile home park, about 25 miles north of the city of El Cajon, in San Diego County.

On Monday, Eskridge had allowed Thomas to spend the night in her guest room, Deputy District Attorney David Williams III said. Some time Tuesday morning, it is alleged Thomas -- armed with a hammer from the 94-year-old's toolbox -- went into Eskridge's bedroom and beat her to death.

Eskridge was found by paramedics who responded to a medical alert bracelet she was wearing at about 11:30am, KGTV reported.

Authorities declined to comment on a possible motive for the attack. Williams, however, said Eskridge had regarded Thomas as "a trusted friend."

Thomas was arrested Wednesday and remains in custody, with El Cajon Superior Court Judge Charles Ervin setting bail at $3.5 million.

If found guilty of first-degree murder, he could face up to 26 years in prison. He returns to court on May 17 for a preliminary hearing.