in the book fawaid ul fawad, which contains statements/lectures of khwaja nizam ud deen oolia, we find khwaja narrated the incident of martyrdom of mola ali asws, then his student asked

was this abdur rehman bin muljam muslim?

he replied: yes he was, but then he got on the side of mawia

[fawaid ul fawad, page 362]

let us see the scans


with loads of thanks to brother syed hasni; see the thread in urdu language