SACRAMENTO, Calif. -- A man accused of killing a Sacramento woman shot himself to death Thursday following a standoff in Fresno, police say.

The suspect, 28-year-old Ma Phompong, was found with a self-inflicted gunshot wound to his head inside a relative's four-plex apartment in the 3700 block of E. Clay Avenue in Fresno.

Sacramento officers found a woman stabbed to death Wednesday evening on Price Court in Sacramento.

The woman's husband was severely beaten and remains at UC Davis Medical Center in Sacramento.

Phompong -- who was described as a parolee and a registered sex offender -- is accused of taking the couple's Toyota Tundra truck and driving to Fresno.

Police said a .30-30 rifle was taken from the home of the crime scene, and that Phompong may have killed himself with the same weapon.

Jeff Cardinale, a public information officer for the Fresno police, said a SWAT team surrounded a residence in Fresno where the man was believed to be hiding.

He was considered "extremely dangerous" and "most likely heavily armed," Cardinale said.

Tear gas was deployed into the apartment twice. Police later used an EOD robot with a camera to go inside the building, and a picture of the presumed suspect's feet were seen.

The SWAT team entered the apartment after 11 a.m. and went inside a bedroom, where they found the suspect dead and a rifle near the body.

The name of the slain woman was not immediately released.

Her injured husband was identified as Bobby Johnson, also known as "Pops."

Witnesses in Sacramento told the police that the man might be heavily armed because of what he found inside the house.

"Pops collected black powder guns and knives," the victim's relative, Diana Harp, said.

LaToya McGee, a neighbor of the slain woman and Johnson, described them as a "nice couple" who had been married for many years.

McGee said Phompong used to live in her garage, and that he used to work for the couple who were involved in the attack.

"It's just shocking," McGee said.

The victim's brother, Richard Johnson, said he couldn't think of anything that would have prompted the killing.

Police said Phompong had been on parole for assault with a deadly weapon for his role in a 1998 home invasion, where one person was stabbed to death.

Phompong had recently moved or resided in the Sacramento area, police said.