SAN DIEGO - A Mira Mesa man charged in his wife's beating and choking death testified Monday that she fell down a flight of stairs in their home after they had sex and watched a movie.

David Ditto, 44, is charged with murder in the death of 38-year-old Karina Ditto.

The defendant said his wife had gone upstairs to use the bathroom the night of March 11 when he heard a cat screech and a loud "thud, thud, thud, thud, thud'' coming down the stairs.

Ditto said he got up off the couch and found his wife lying at the base of the stairs.

"She was not moving,'' the defendant said. "I said, `honey, honey are you OK?''

The defendant said he tried CPR, then pulled his wife alongside a dresser near the foot of the stairs, Ditto said the victim suddenly started moving and waving her arms, reaching for the back of her head.

When his wife stopped moving again, Ditto said he called 911.

Paramedics and firefighters who responded to the 911 call shortly before 1 a.m. expected to see a victim injured from a fall, but what they found was very different, said prosecutor Claudine Ruiz.

Paramedics noted injuries to the victim's right temple and a cut to the back of her head, but there was no active bleeding though the victim was covered in blood, according to the prosecutor.

The defendant also had scratches on his face from his wife fighting back, the prosecutor alleged.

A firefighter was concerned about the circumstances under which the woman was found and called police, Ruiz said.

The victim suffered a brain injury from lack of oxygen and was taken off life support two days later.

Nurses looking at Karina Ditto hours before she died on March 14 noticed extensive bruising on her body, according to the prosecutor.

She had bruising under her scalp, jaw, lip, tongue, chin, shoulder, arms, hands, legs and shins, and even had a fractured rib, Ruiz said, adding that a bruise on the leg was consistent with a footprint.

Ditto testified that he and his wife of 16 years had talked about a separation, but had agreed to stay together.

In her opening statement, Ruiz told jurors that the defendant struck his spouse "over and over,'' and kicked, stomped and choked her in their home while their two children slept upstairs.

Ruiz said the last two years of the couple's marriage had been like a roller-coaster ride, and Karina Ditto was "ready to get off.''

By August 2010, she had decided she was going to leave her husband, and in November, the defendant took out a life insurance policy on his wife in case of accidental death, Ruiz said, telling the jury that the bruises on the victim's body showed "this was no accident, this was murder.''

But defense attorney Keith Rutman said the couple -- despite earlier problems -- had patched things up, were living a happy life and loved each other.

"She died of a horrible accident,'' Rutman said in his opening statement. "Falls kill people ... and a fall killed Karina Ditto.''

The Dittos were a close-knit family and were the envy of their neighborhood, according to Rutman, who said paramedics first on the scene asked the wrong questions and got the wrong answers.

The victim flailed her arms after she was knocked out and that's when she scratched her husband's face, Rutman told the jury. Ditto faces 25 years to life in prison if convicted.