Cops in California say they have arrested the girlfriend of a murder suspect after she broke into the home where he allegedly killed his wife and mother-in-law so she could destroy evidence.

The Contra Costa County District Attorney”s Office said on Tuesday that it arrested 45-year-old Yan Wang on charges of accessory after the fact, residential burglary and destroying evidence. Prosecutors say she was in a romantic relationship with 43-year-old Howard Wang (no relation) who is accused of murdering his wife Linlin Guo and his mother-in-law Beimin Cheng.

Walnut Creek police first responded around 11:45 p.m. on Sept. 18 for a possible shooting at a home in the 100 block of Kelobra Court. Cops rushed to the home where they found Guo and Cheng dead. Detectives identified Howard Wang as the suspect and arrested him on the murder charge.

Prosecutors allege Yan Wang tried to help her boyfriend “avoid arrest, trial, conviction, and punishment” for the slayings of his wife and mother-in-law. She also is accused of destroying cellphones to “prevent evidence from being produced.” She allegedly broke into the home where Howard Wang and Guo lived with “intent to commit larceny” the day after the murders.

Cops arrested her on Sept. 24 near her home in Oakland and she was formally charged on Monday. Both suspects are in the Contra Costa County Jail without bond. They are next slated to appear in court on Friday.

Authorities say the murder suspect threatened to kill his wife in August 2024 and prevented her from reporting a crime to cops on Jan. 7, 2023. Police did not expand on those allegations, nor have officials divulged a motive for the murders.

Local Fox affiliate KTVU reported that at Howard Wang’s first appearance, there was a physical altercation between Yan Wang and Linlin Guo’s family members after the defendant’s mistress showed up in court. The station, citing court documents, also said that Howard Wang filed for divorce in January 2024 but sought to have the matter dismissed months later.

“This case serves as a sobering reminder of domestic violence’s far-reaching consequences,” Contra Costa District Attorney Diana Becton said in a statement. “Our office will pursue justice with the seriousness and urgency this tragedy demands.”