A prosecutor weighs on charging the parents of Ethan Crumbley, who is accused of killing four students at Oxford High School in Michigan.

According to the Associated Press, the 15-year-old boy has been charged as an adult with two dozen crimes for the mass shooting at Oxford High School in Oakland County on Tuesday.

Oakland County Prosecutor Karen McDonald said Thursday that Crumbley's parents were the "only individuals in the position to know the access to weapons," adding that the gun "seems to have been just freely available to that individual."

Police said Crumbley's father, James Crumbley, purchased the Sig Sauer 9mm handgun allegedly used in the shooting, Fox 2 News report. 

According to investigators, the semi-automatic gun was bought legally by James at a local shop last week and was possibly a Christmas present for Ethan.

McDonald said the actions of Crumbley's parents went "far beyond negligence" and that a charging decision would be announced by Friday.

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Possible Charges on Ethan Crumbley's Parents

Experts noted that parents in the U.S. are rarely charged with school shootings involving their children, even when most minors got guns from a parent or relative's house.

Oxford High School officials met with Ethan Crumbley and his parents the day before and the day of the shooting. The teachers warned of his behavior at school, which included drawing violent pictures in class.

However, school officials never told police or the school resource officer placed in the district. Crumbley's behavioral record at the school was reportedly clean, heading into the recent incidents this week.

The Oxford High School did not issue a comment regarding the meeting with Crumbley's parents before the mass shooting.

McDonald said they are prosecuting the shooter to the fullest extent, but she added that there are other individuals who should be held accountable.

"We are looking at the whole situation and we will hold accountable, to the extent possible, anybody we think committed any criminal act," she noted.

The prosecutor also implied that Crumbley's parents were under scrutiny when she filed charges against their son on Wednesday.

Michigan Mass Shooting

Ethan Crumbley is not only accused of shooting dead four classmates but also injuring seven others at Oxford High School.

The Michigan teen is currently facing 24 charges, including one count of terrorism and four counts of first-degree murder, which carry a maximum sentence of life in prison, Independent reported.

Investigators noted that they found numerous evidence showing Crumbley allegedly plotting his attack well in advance, with outlines of plans in a journal. 

The Michigan teen had also reportedly shared his intentions in two videos before the shooting. Crumbley also shared social media accounts with a photo of the handgun he used in the mass shooting.

Students and parents had described a sense of unease on the campus weeks before the mass shooting. They recalled that there were threats of violence spreading for some time.

As shown in a surveillance video, Crumbley came out of the bathroom with the semi-automatic handgun. Prosecutors said the teen fired the gun "methodically" but seemed to be targeting people at random.

Police noted that Crumbley had fired at least 30 rounds in those five minutes of shooting, with 18 rounds remaining in his handgun when he surrendered.

Tate Myre, 16; Madisyn Baldwin, 17; and Hana St. Juliana, 14, were pronounced dead at the scene. Meanwhile, 17-year-old Justin Shilling died in a hospital the next day. Six more students were injured and a teacher.

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This article is owned by Latin Post.

Written by: Mary Webber

WATCH: Oxford High School Shooting: Ethan Crumbley Charged as Adult - From FOX 7 Austin