EPHRATA - A Royal City man was found guilty of beating his girlfriend with several items for about an hour.

Grant County Superior Court Judge Evan Sperline found Wilmer S. Guerrero, 20, guilty of second-degree assault following a three-day trial. Guerrero waived his right to a jury trial, according to court records.

Prosecutors initially charged Guerrero with first-degree assault in October, following the attack.

Guerrero's previous convictions include, assault, driving under the influence, resisting arrest, attempting to elude, tampering with a witness, driving while license suspended, malicious mischief, residential burglary, theft and taking a motor vehicle without permission, according to the Grant County Prosecutor's Office. When combined with his present convictions, Guerrero faces a sentencing range of a year and a month to a year and five months in prison.

"We proved in this trial that Guerrero perpetrated a significant and brutal act of domestic violence on the mother of his child," Prosecutor Angus Lee stated. "We proved there were significant injuries, and we proved that multiple weapons were used in the assault. Due to the level of injury inflicted, and the fact that the defendant used multiple weapons, to include a wrench, a space heater, and a car jack, we will be seeking the maximum sentence allowed under the law." Guerrero and the victim, a 17-year-old girl, were living in a bedroom in the back of Guerrero's father's shop on Crook Loop Southwest in rural Royal City, according to a Grant County sheriff's report. Guerrero returned to the room at about 1 a.m. on Oct. 28 intoxicated.

After arguing with Guerrero about coming home late, they were laying in bed and he accused her of cheating on him, and hit her in the head with a closed fist, according to the police report. After hitting her with his fist, he picked up a portable heater and struck her. He continued to accuse her of cheating, telling her he would stop attacking her if she confessed.

At one point the girl was able to rise, and tried to escape, but Guerrero caught her in the garage, throwing her to the ground, according to the police report. She made up a name to try and get him to stop, but Guerrero dragged her back to the bedroom and beat her for about an hour. He used a portable heater, big wrenches and a glass cup.

She was able to escape after Guerrero brought her to his parent's residence to clean up, according to the police report. She was able to get into his mother's bedroom and lock the door, while alerting Guerrero's parents.

When police arrived, they found the woman in a bed covered with blood, according to the police report. She had severe lacerations to her head and her left hand was swollen and appeared to be broken.