"At this time, we haven't seen any evidence of criminal activity that will lead us to seek charges," police spokesman David Bayless said.
The collapse happened about 12:30 a.m. Sunday in the city's affluent Lincoln Park neighborhood at a three-story building that was converted in 1998 from five apartment units to three. City officials said the third-floor wooden porch was apparently rebuilt at the same time.
City Building Commissioner Norma Reyes said permits were issued for the conversion work, but no construction permit has been found yet for the porch.
"We're not sure if they had the proper permit to put up the porch," said Breelyn Pete, spokeswoman for the Buildings Department.
A structural engineer conducted a preliminary examination and determined that the porch was sound before the collapse, Reyes said Sunday. City officials are investigating whether the porch gave way because it was overloaded.