Authorities are offering a $25,000 reward for info leading to the arrest of the person(s) who set fire to a two-story Portola apartment building. The fire injured six firefighters, with two sent to the hospital, on Feb. 6. Former SF Mayor Willie Brown verbally ripped the chaps who did this a new hole today at a press conference today. "We have to find the culprit," Brown vented. "San Francisco's finest has been threatened." But the good news in all this is that if any of you know the culprits, call the Arson Task Force's anonymous tip line at 415-575-4444. (Of course, to collect, you might want to give them your name.)