we are boosting the visible presence of officers in our system including our cay nan unite-- canine unitt if you see something say something. many riders want to say safe during their commute. >> it will make me feel better just because it gives us more hope that everything is good and there's no risk to peoples lives. >> for now bart won't say how long its heightened security measures will last. it is worth repeating. bart says there have been no specific threats against the transit system. abc 7 news. >> all right. thank you. >>> we sent out this breaking news push alert as soon as we confirmed the news. be the first to know by downloading the abc 7 nt. >>> iestigating the deaths of two visitors at yosemite. they recovered bodies of a man and woman that fell from taft point with an elevation of 7,500 feet. they will only say it is under investigation. the victims have not been identified. >>> in you this morning a flight delay at the san jose airport after a flight attendant said she saw something us pissuspici. they swept the plane there. nothing dangerous was found. the plane was dela

in their meeting, and that their converstation had nothing to do with what would happen in the s unittesrs later. >> jacoby: it was known toce ok in 2014 there was potential for russian disinformation campaigns on facebook. fo yes. and there were disation campaigns from a number of fferent countries on facebook. you know, disinformationre campaigns regular facet of facookery abroad. and... i mean, yeah, technically that should have led to a learning experience. i just don't know. >> jacoby: there was plenty that was known about the potential downsides of social media and facebook-- you know,otential ar disinformation, potential for bad actors ase. were these things that you just weren't paying attenon to, or were these things that were kind of conscious choices to kind of say, "all right, we'na kind of abdicate responsibility from those things and just keep growing?" >> i definitely think we've been paying attention to the things w thknow. and one of the biggest challenges here is that this is really an evving set of threats and risks. we had a big effort around scams. we had a big effor