Swindon Wildcats went further behind at the start of the second period when Simon Butterworth scored at 22.10.
And matters got worse for Cats when Slamiar added his second at 29.01 to put the home side well in control.
Cats did pull a goal back on 31 minutes when Robin Davison and Richardson combined to set up Petkoff to score.
However, after John Wheaton and Richardson both went close Sheffield went further ahead when Slamiar completed his hat-trick at 39.19.
FINAL PERIOD REPORT TO FOLLOW...
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article