I also saw those reports. I found that WNYC's "Breaking News Consumer Handbook"[1] was a useful tool for sorting through the various reports. Many of the reports citing a "domestic dispute" either cited other news outlets (in some cases, without even citing any particular outlet) or attributed its facts to vague "reports."
Of the sources I was following, KRON seemed to have the lowest standards (at times even publishing contradictory statements as fact in consecutive paragraphs of their story), while NYT had the highest (but, correspondingly, stuck with the "the shooter has not been identified" line for hours longer than most other outlets).
I find looking at the Wikipedia history page [2] for incidents like this educational for understanding how our knowledge of events changed over time. In this case, the Wikipedia article attributed the domestic dispute claim to two law enforcement officials who spoke to CBS News. The cited CBS News article no longer supports the facts in the Wikipedia article, but presumably did at one time.
