http://www.jackssmallengines.com/briggs_and_stratton_model_locator.cfm
That should help a little. Also, from my research, I think they were built by...
X2. 'Nuf said. The other thing, that I have yet to find an answer to, is how will you register the criminal's weapons? Since prior case law says that...
Snapper 21401P, 4HP B&S (grass mutilator) 5/1987 vintage
BOB-CAT M21-4SPZ 4HP B&S (semi-retired) 1/1983 vintage
Snapper 21350 3.5HP B&S (perma-loan) 9/1980 vintage, with side chute and bag/bag chute
Various and sundry other machines as donors, fund-raisers!*
*though not always...