SAN DIEGO -- A methamphetamine addict who beat, tortured and strangled his longtime girlfriend because he was unhappy with her in bed was convicted Monday of first-degree murder and other charges.

A jury spent six days deliberating the case before finding Jack Henry Lewis, 39, guilty of murder, torture and a special circumstance allegation that the murder of 48-year-old Jan Hasegawa occurred as she was tortured.

Lewis looked at his attorney, Juliana Humphrey, as Judge John Einhorn read the verdicts.

Outside court, friends and family of the victim hugged each other and cried.

Jurors will reconvene Thursday to begin hearing evidence in the trial's penalty phase, which is expected to last three days. Jurors must recommend a sentence of death or life in prison without the possibility of parole.

Deputy District Attorney Nicole Cooper told jurors in her closing argument that Lewis beat and strangled Hasegawa on Sept. 8, 2005, because she wouldn't perform a sex act on him.

Cooper said Lewis intended to inflict extreme pain on Hasegawa, hitting her with his fists and striking her with a large flashlight, leaving more than 150 bruises on the front of her body.

Lewis had broken Hasegawa's arm earlier in their relationship when she tried to leave him, the prosecutor said.

Hasegawa told friends that Lewis was violent, but that he would stop abusing her if she could just love him more, Cooper told the jury.

"Jan's mistake was loving Jack Lewis ... and staying with him," Cooper told the jury. "But she did not deserve to die."

The defendant's attorney said the couple's use of methamphetamine set in motion a series of events that neither contemplated.

By the summer of 2005, their methamphetamine addiction was so bad "that neither of them could stop this tragedy," Humphrey said in her closing argument.

She said Hasegawa's killing was not willful, deliberate or premeditated.

"There is no intent to kill," the defense attorney said. "There was no thinking that night, or that morning ... at all."

Humphrey said Lewis had no motivation to kill Hasegawa, saying he loved her and she loved him. Hasegawa took care of Lewis emotionally and financially, his attorney said.

Co-defense attorney Douglas Miller told the jury that in recent years, Lewis and Hasegawa both started injecting methamphetamine and engaging in violent sex acts that including choking while climaxing.

Miller said Hasegawa could have died of a heart attack caused by a methamphetamine overdose and said Lewis was in a meth-induced delirium when his girlfriend was killed.

The defense had urged the jury to convict Lewis of voluntary manslaughter.