Investigators are studying videos from the hotel in Kingston, Jamaica, where Pakistan coach Woolmer, 58, and the rest of the Pakistan team were staying at the time of his murder on March 18.
Police say Woolmer was strangled in his room, a day after World Cup minnows Ireland stunningly knocked Pakistan out of a competition they had won in 1992.
Ashraf told Sky Sports: "I am absolutely convinced, I have no information or proof that there is any corruption in Pakistani cricket at all.
"There is no idea or anything of that nature to suggest that there is any corruption involved or any match-fixing linked to the Pakistani cricket team.
"This has been a terrible ordeal, the boys have been through terrible stress. No one could have imagined that in a gentleman's came like cricket things like murder could happen so it's been a tremendous shock for all of us.
"We have been the victims of this dastardly crime - our boys have been through hell - so it's vital that whoever is responsible is brought to book.
"Our boys are on their way home to be with their families - you can imagine what their families have been going through."
Nasim Ashraf also revealed that Woolmer had decided to retire from coaching following the World Cup but that he would remain in the sport at a grass roots level.