James Crumbley's threatening jailhouse phone calls where he vowed to get ... trends now

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.'

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.