Man told police he killed for revenge in Mattawa homicides

A man accused of gunning down three people in a rural Eastern Washington town told police he was angry at the men for raping a friend, according to new documents. J. Guadalupe “Lupe” Martinez-Lopez, 24, is in custody on $2.5 million bail after appearing in Grant County Superior Court on Thursday. He’s charged with three counts of first-degree murder in connection with the Monday night shooting deaths of Pedro Rivera Sanchez, 21, and two men whose identities have not been confirmed. Police arrested Martinez-Lopez Tuesday at a Sunnyside restaurant – about 45 miles from Mattawa – shortly after a gunpoint robbery at a nearby convenience store. Grant County Sheriff’s detectives think Martinez-Lopez used the same .45 semi-automatic pistol in the murders and to rob the store of beer and money. He allegedly went to the store after sitting down with his girlfriend and two others for dinner Tuesday night and realized he didn’t have any cash. Police were waiting at the restaurant when he came back. Martinez-Lopez told police he went to the Mattawa home of one of the victims, tentatively identified in court documents as Roberto Oaxaca. Five others were at the home watching television when Martinez-Lopez and Oaxaca left in a Dodge Intrepid, according to court documents. Witnesses said Martinez-Lopez returned a half hour later, said the car had slid off the road and “started laughing, then pointed a pistol into the living room and fired the gun.” Detectives found Sanchez and a man identified in court documents only as Diablo shot to death in the home. Oaxaca was found shot to death at Road U S.W. and Road 26 S.W., which is near the home. Martinez-Lopez reportedly told police he’d persuaded Oaxaca to leave the home “so he could shoot him.” He told police he shot Oaxaca after telling him “he was going to pay” then drove the Intrepid back to the home. “Martinez-Lopez said he told the occupants who were seated on the living room that what they did was wrong,” according to court documents. “He said it appeared as if they were going to stand up so he started shooting before they could do anything to him.” No details of the alleged sexual assault the suspect claimed to be avenging were available. Grant County Undersheriff John Turley said Martinez-Lopez didn’t name the alleged rapist and gave few details. “He was more impressed that he was able to get away with what he thought he got way with,” Turley said. “Pretty horrible person. I’m glad we got him off the street.” Witnesses identified the shooter only as Lupe, but Mattawa police recognized the name from an investigation into robbery and boat motor thefts. Sunnyside police arrested the suspect. Turley credited interagency cooperation with helping the investigation. Martinez-Lopez’s girlfriend told detectives she and her friends had been going to the home where the shooting occurred to use methamphetamine, according to court documents.