Marr 's brother came under scrutiny , since he was rumoured to have had a disagreement with him , but after being interrogated for forty - eight hours , he was exonerated .
Marr had a firm alibi .
Marr 's brother came under scrutiny , since he was rumoured to have had a disagreement with him , but after being interrogated for forty - eight hours , he was exonerated because he had a firm alibi .