BART police Sgt. Tom Smith had asked his superiors to assign the department's SWAT team to take part in high-risk searches of residences to ensure safety, but was rebuffed, before he was shot dead last month by a fellow officer during a search in a Dublin apartment, sources told The Chronicle.

There's no indication Smith made the same request before the Jan. 21 search that turned tragic, with Smith accidentally shot by Detective Michael Maes. But the question of whether the BART officers who took part in the search were sufficiently trained for the job has raised questions inside and outside the transit agency.

While members of the SWAT team and several other BART officers have been sent to specialized training on making high-risk entries into buildings, none of the officers who went to Dublin had such training, according to the sources.