The late Whitney Houston's daughter Bobbi Kristina seemed to have turned a page on her troubled life when she married Nick Gordon earlier this year.

Although some raised eyebrows about Bobbi, 21, marrying the guy she grew up with as a kind of adopted brother, she insisted: "I'm finally happy."

But now, an explosive family feud has developed and Breaking Celebrity News.con has learned Gordon is making threats online against Whitney's nephew (and Bobbi's cousin) Gary Michael Houston!

It all started last December when Whitney's rapper nephew, Gary, reportedly upset at Gordon for talking trash about the family, beat him up at a Houston family party.

Gordon brought up the incident on Twitter this month, and now, his tweets have become more explosive, as he appears to be taunting Gary and his mother, Pat Houston,  and posting alarming pictures of guns!

On March 16, Gordon tweeted, in an apparent reference to Nightmare on Elm Street's killer Freddy Krueger, "Pat b***h Gary M I'm Freddy to y'all n****az.  F*** you suck my d***."