A sacked ABC crime reporter has unloaded on the broadcaster and former colleagues, saying they had betrayed his sources and that leaked claims about his work practices were “complete f***ing bulls***”.

The ABC is investigating allegations that reporter Mahmood Fazal had used the same source in different guises one year apart.

Mahmood Fazal has defended his work, arguing it had gone through proper processes, and accused his critics of painting him as a “diversity hire”.