The Los Angeles County District Attorney’s Office declined to file charges against the mother of the shooter in the tragic fatal shooting at Saugus High School, which took place a year ago Saturday, sheriff’s homicide detectives confirmed Thursday.

On Nov. 14, 2019, 16-year-old Nathaniel Tennosuke Berhow opened fire in the quad at Saugus High with a ghost gun that was assembled at home, shooting five schoolmates and killing two before fatally turning the gun on himself. Killed were 15-year-old Gracie Anne Muehlberger and 14-year-old Dominic Blackwell.

Homicide detectives said Thursday they only looked at charges against one person after their monthslong investigation: the shooter’s mother, Mami Matsuura-Berhow.

“We presented a case on Nathaniel Berhow’s mother to the District Attorney’s Office,” said Sgt. Guillermo Morales, “and they declined to file charges on her for (contributing to) the delinquency of a minor and criminal storage of a firearm.”

The case was rejected on Oct. 23, according to prosecutors. A spokesman for the D.A.’s Office confirmed Thursday evening the case was rejected due to lack of evidence to sustain the charges, but more information was not immediately available regarding why the case was declined. It was presented approximately two weeks prior, according to Morales.

“There were firearms that were found in the residence that were not locked up,” Morales said, noting both charges were related to the guns. “That was pretty much it.”

Morales mentioned back in July that there were a number of avenues that were being investigated with respect to how Berhow obtained the gun. Morales said he believes the gun used in the shooting, which was considered a “kit gun” or “ghost gun,” was originally assembled by Nathaniel’s father, Mark Vincent Berhow, who died of a heart attack in December 2017.

The Signal previously reported the elder Berhow was an avid hunter who owned at least a half-dozen firearms. (In response to the shooting, the families of Gracie and Dominic have filed a federal lawsuit against the Bureau of Alcohol, Tobacco and Firearms, as well as Attorney General William Barr, seeking to have ghost guns regulated the same as firearms.)

Morales confirmed Thursday there were no additional charges being considered, and he considered the investigation closed in that respect. However, he also said that after nearly a year, there was still no clear motive for the shooting he was willing to discuss.

“Of course, we have some theories on why, but I’m not going to go into that,” Morales said. “As far as a solid reason, I don’t have it.”