SAN ANTONIO (AP) _ Police arrested a suspect Firday in the slaying of the 76-year-old matriarch of a San Antonio restaurant family who was found dead in her home after firefighters responded to a fire there.

Details of the arrest were to be released at a Friday morning news conference, the San Antonio Express-News reported.

Police made the arrest after the police found her silver Mercedes that was stolen at the time of the killing.

The body of restaurateur Viola B. Barrios was found Thursday. Police declined to release any details.

Officials said the rear of her house was intentionally set afire.

Barrios started Los Barrios as a young widow in 1979, hoping to support her three children. For nearly 30 years she worked seven days a week, making tortillas and enchiladas and managing the restaurant that became one of San Antonio's best-known.

In just two weeks she was set to move out of the modest home her husband had built to a large estate.

Authorities said a motive for the slaying is not yet known, but her son, Louis Barrios, said he suspects a botched burglary.

"It's just amazing to me that this has happened," Louis Barrios, 47, said through tears.

Her son, chief executive officer of Los Barrios Enterprises Inc., told the San Antonio Express-News for its Friday editions that his mother's life "represented the opposite of her death, not taking, but giving."

For instance, Viola Barrios had purchased 18 mattresses this week to take to her hometown in Mexico Bustamante, Nuevo Leon, for residents who are without beds.

In a statement prepared for her upcoming induction to the Texas Restaurant Association's Hall of Honor, she wrote, "it seems that I also have an unofficial job of lending money to my employees in need. Most of those unsecured loans often go unrepaid but in times of emergencies, how can I say no."

Barrios moved to San Antonio with her father and four siblings after her mother died when she was a young girl. Later, she married Jose C. Barrios, a popular San Antonio media personality. He was killed in 1975 in a traffic accident.

Barrios eventually opened a second restaurant and both have won praise from food critics across the nation. Barrios' daughter, Diana Barrios-Trevino, has published a cookbook of her mother's recipes.

Juana Lara, who began as a hostess 17 years ago and is now a waitress, said Barrios was a "wonderful, wonderful person" who treated her employees like her children.

She said that just last week, her boss had taken her to show off her new house.

"She was so excited," Lara said.

Copyright 2008 The Associated Press.