All of the shouts of "Burn it down!" "Burn that mother--" etc., followed by the exchanges over the radio ("Seven burners deployed and we have a fire." etc.) add up to something of a smoking gun, as it were.
According to this CNN report
S.B. County Sheriff John McMahon acknowledged that "the cabin caught fire after police shot tear gas canisters into it."
"Although the canisters included pyrotechnic tear gas, which generates heat, 'We did not intentionally burn down that cabin to get Mr. Dorner out,' McMahon said."
If their intention actually was to burn him to death, this is a really nifty bit of prevarication.