Abettment of crime may be by ommission or commission is it not illegal?

I heard Mr Arnab Goswami last night on Times now. Here is one query .Please enlighten.If during investigation a n prominent political leader pubicly denounces encounter with terrorist and goes to the homes of the accused to show sympathy with their families and gives the impression as if the enounter was managed .Is it not interference in the investigation or abettment and is it desirable at all.