A 44-year-old woman has been arrested on suspicion of fatally stabbing her wife with a samurai sword during an argument at their home in San Dimas last week, authorities said.

On July 18, investigators responded to the 300 block of South Huntington Avenue, between Arrow Highway and Cienega Avenue, around 3:30 p.m., regarding the stabbing.

According to sheriff’s officials, investigators have now determined that Weichien Huang and her wife were arguing at their home and Huang attacked her wife with a sword.

Huang’s wife, Chen Chen Fei, was pronounced dead at the scene, authorities said.

“At some point, Huang attacked Fei with a sword,” sheriff’s officials said. “Fei’s mother was also attacked and severely injured; however, (she) was able to gain control of the sword and fled the residence looking for help.”

Fei’s mother was taken to a hospital and was listed in stable condition from injuries sustained from the assault.

It was unclear what prompted the attack.