(Longview, WA)  --  Authorities continue to investigate a murder-suicide at a Longview apartment.  Police believe David Pittore-Montiel shot and killed his seven-year-old son, Michael, before taking his own life yesterday morning at the apartment in the 900 block of 8th Avenue in Longview.  Investigators tell Fox-12 the boy's mother lives in California and was notified about the deaths.  Police say they heard gunshots while responding to a report of a suicidal man in the apartment.