SAN DIEG -- A 41-year-old ex-convict pleaded guilty Thursday to first- degree murder for killing an 80-year-old Hemet man, encasing the body in concrete and using the victim's credit cards on a spending spree.

Thomas Jeffrey Brooks also admitted to numerous counts of second-degree burglary, and will receive 75 years to life in prison when sentenced by Judge David Gill on June 22.

A special circumstance allegation of murder for financial gain, which would have made Brooks eligible for the death penalty, was dismissed in exchange for the plea.

Brooks was in federal prison when he became pen pals with victim Edward Clayton Andrews, Deputy District Attorney Dino Paraskevopoulos said.

The defendant was released in 2007, moved into a Hemet mobile home with Andrews and began a same-sex romantic relationship with him, the prosecutor said.

On May 31 of 2008, a neighbor saw Brooks go into the mobile home. When the neighbor asked Andrews if he was okay, he replied "yes," Paraskevopoulos said.

"After that he was never seen again," Paraskevopoulos said.

An ATM surveillance camera at a bank in Orange County recorded Brooks withdrawing $500 from Andrews' account that night, the prosecutor said.

The burglary charges stemmed from Brooks buying hundreds of dollars of goods with the victim's credit cards at various stores at the Citadel Outlets in Los Angeles, the Glendale Galleria mall and various businesses in Los Angeles and Orange counties over the next week.

The prosecutor said Brooks withdrew $24,000 from the victim's accounts and took money from $108,000 of phony check deposits.

Several people who knew Andrews testified at an earlier hearing that the victim expressed fear of Brooks.

Brooks had been allowed to build a concrete centerpiece for a rock garden at his landlord's Alabama Street home. When neighbors learned he'd been arrested on financial fraud charges, they partially broke the concrete and discovered a human foot, according to Paraskevopoulos.

Andrews, who died of asphyxiation, had been wrapped in a blanket and plastic tarp, with duct tape and chicken wire used to secure the remains in the homemade tomb, the prosecutor said.

Arlo Elizarraraz, 20, an acquaintance of Brooks who helped encase the body and lived off some of the money, pleaded guilty to 55 felony counts --including being an accessory to murder -- and was sentenced last month to nine years in state prison.

Brooks had earlier been in federal prison for a 1990 arson conviction in Charlotte, N.C.