police arrested denis pereirade macedo on suspicion of three counts of homicide. he was found uninjured near the crash site saturday night. investigators say his car broad sided the victim's car. killing the driver and her two sons. a 4th person a girlfriend of the victim remains in the hospital. >>> an investigation is underway to determine how a homeless man gained access to the top of a elevator before he was crashed to death. ktvu's jade hernandez is in san francisco at the montgomery street station where the accident happened. jade? >> that is right. the incident happened at the station, we are live tonight and bart doesn't know who the man was but he was in a place he shouldn't have been and it cost him his life. >> reporter: trains ran on schedule tonight but last night a man heard a horrible noise. police discovered a homeless man on top of the elevator crushed. >> dangerous. unusual, upsetting, disturbing. >> reporter: the homeless usually seek shelter to get away from the cold. one example was depicted in the movie the pursuit of happiness. barted today

denis pereirade macedo was booked into the county jail on murder and hit and run charges. he was found uninjured near the crash site. his car broad sided the victim's car. all three were pronounced dead tea scene. >>> -- at the scene. >>> high school was placed on lock down this afternoon. the school was on lock down for an hour after police say there was a report someone was locked in the bath room with a knife. investigators didn't find anything. all students and staff are safe. >>> the work to restore a san francisco neighborhood damaged by a burst water pipe could take months. crews were working in the area today, they have closed the turn off to reduce traffic on 15th street and they will remain clued during the work. that work could take 3-6 months. >> hopefully we don't have a full 3-6 months of active construction but there will be work in the street, for the several months coming. >> the burst on february 27 and opened up several sink holes. three holes remain head tagged and three homes are yellow tagged. as for the cause of the break, that is still under investi