Threatening jailhouse phone calls from the father of Oxford school shooter Ethan Crumbley have been released, with him vowing revenge on the prosecutor who charged him with manslaughter. 

James Crumbley was sentenced earlier this week alongside his estranged wife Jennifer to 10 to 15 years behind bars for their part in their son's massacre. 

Authorities have since released audio recordings of calls in which Crumbley threatens Oakland County Prosecutor Karen McDonald. 

In the audio, obtained by the Detroit Free Press, Crumbley can be heard saying: 'Karen McDonald, you are going down. Yeah you stupid b*****s at the f*****g jail, go ahead record this call, send it to Karen McDonald.

'Tell her how James Crumbley is going to f*****g take her down. She will not have a law license when I get done with her.

'Karen McDonald will be working at f*****g McDonalds, cause she ain't gonna be able to get a job anywhere else.'

James Crumbley was sentenced earlier this week, seen here, alongside his estranged wife Jennifer to 10 to 15 years behind bars for their part in their son's massacre

Authorities have since released audio recordings of calls in which Crumbley threatens Oakland County Prosecutor Karen McDonald, seen here

In another, Crumbley can be heard saying: 'She's really got it coming to her when I f*****g get out. Your ass is going down and you better be f*****g scared.'

Another adds: 'You know what, three months from now it is going down, when I get out of here I am on a rampage Karen.

'Yes Karen McDonald your ass is going down and you better be scared.' It remains unclear as to who Crumbley was on the phone to at the time. 

An investigator at the Oakland County Sheriff's Office told the outlet: 'Most of the contents of the messages I have reviewed appear to be Mr. Crumbley complaining about court proceedings and courtroom tactics and Mr. Crumbley making comments about winning the matter in court and making Karen McDonald look bad to the public '

The outlet obtained the recordings via Freedom of Information laws, which also uncovered a police report filed by the prosecutor's office into the calls. 

The report asked sheriff's office to investigate what they deemed 'harassment and threatening' phone calls. 

The calls were mentioned in the first day of Crumbley's trial, which caused a spat in the courtroom and for the jury to be sent home for the day. 

Prosecutors raised an issue with Crumbley's jailhouse communications, which his lawyer objected to the issue of being made public. 

Crumbley's lawyer Mariell Lehman has maintained that Crumbley was not threatening to physically harm McDonald but venting frustrations. 

James Crumbley is seen crying in court Monday as he and wife Jennifer received a landmark 10 to 15 year sentence for their son Ethan's 2021 school massacre that murdered four 

James and Jennifer Crumbley sat at the same table ahead of their sentencing, where they received the maximum possible sentence of 10 to 15 years 

During sentence the phone calls were again brought up, with prosecutors arguing they warranted a stiffer punishment. 

Judge Cheryl Matthews agreed and told Crumbley that he 'threatened the wellbeing of the prosecutor.'

His son Ethan, then aged 15, opened fire at the school in Oxford, Michigan, and murdered Hana St. Juliana, Madisyn Baldwin, Tate Myre, and Justin Shilling. 

Ethan was sentenced to life in prison without parole for the murders, after being convicted of 24 felonies including terrorism. 

Crumbley and his wife Jennifer were convicted at separate trials earlier this year, with juries finding they ignored Ethan's pleas for help and bought him a firearm. 

Their sentences will be served minus the near-two-and-a-half years they have already served, and they will be barred from contacting to their son's victims' families.

The two are the first parents in the US to be held responsible for a child carrying out a mass school attack.

McDonald said Crumbley ignored signs that his son was deeply disturbed, did not get him the help he needed, and did not safely store the firearm in the family home.

Ethan Crumbley pleaded guilty to his crimes and is currently serving life in prison without the possibility of parole, after murdering four classmates in the Oxford High School shooting in 2021

Justin Shilling, 17, (left) and Tate Myre, 16, (right) were two of four students killed in the senseless shooting at Oxford High School in Michigan

Madisyn Baldwin, 17, (left) and Hana St Juliana, 14, (right) died in the 2021 shooting rampage at Oxford High School in suburban Detroit 

McDonald also presented the jury with texts that Ethan Crumbley had sent to a friend and journal entries he had written in the months leading up to the shooting.

In those, he talked about wanting medical attention and hearing voices, but he was worried his parent would be 'pissed.'

On one occasion, according to a text message to a friend, Ethan asked Crumbley to take him to the doctor, but his dad 'gave me some pills and told me to suck it up.'

Defense attorney Mariell Lehman argued that James Crumbley could not have possibly foreseen that his son would carry out a mass shooting.

Crumbley, accompanied by Ethan, bought a Sig Sauer 9 mm handgun over Thanksgiving weekend in 2021. 

Oakland https://nhanlambangcap24h.com/ County Prosecutor Karen McDonald holds the murder weapon at James' trial, as jurors heard how he purchased the firearm for his son despite his disturbing behavior 

The boy called it his 'new beauty' on social media. His mother described the gun as a Christmas gift and took him to a shooting range.

Four days after the purchase, the parents went to Oxford High to discuss a violent image their son had drawn on a math assignment.

Alongside the drawing including phrases that said: 'The thoughts won´t stop. Help me.' There was a gun on the paper that looked similar to the Sig Sauer.

The Crumbleys didn't take him home, and school staff - believing he might be suicidal - also didn't demand it. 

But no one checked the boy's backpack for a gun, and the shooting happened that afternoon.

Before his sentencing, James read a statement where he said his 'heart is broken for all involved', and he stressed that claims he had no remorse for his son's actions were not true. 

'I know the pain and loss will never go away.' 

Michigan

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Audio recordings released of James Crumbley's threatening jail calls