Nick Gordon ''lost it'' when Bobbi Kristina Brown died.

The boyfriend of the late aspiring actress - who tragically passed away in July after six months in a coma - has posted a cryptic message on micro blogging site Twitter about the ''pain'' he is feeling since her death.

Tweeting lyrics from Jay Z's song 'Lost One': ''Can't run from the pain go towards it. Some things can't be explained what caused it. When I lost you I lost it. (sic).''

His tweet comes only days after he was accused of ''injecting'' the late star with a ''toxic mixture''.

The estate claims: ''Bobbi Kristina died after a violent altercation with the defendant [Nick Gordon] after which he placed her in the bathtub unconscious, after he injected her with a toxic mixture.''

They have also accused Nick of trying to avoid the $40 million lawsuit and claim he attempted to cover things up by changing his clothes after the alleged altercation.

Meanwhile, Bobbi Kristina's father Bobby Brown recently insisted he was ''looking forward'' to criminal action against Nick Gordon taking place soon.

He said in a statement: ''In regards to the civil litigation, we believe we know who harmed Bobbi Kristina Brown and his name is Nick Gordon ... I look forward to having the Court hear the evidence in the civil lawsuit and hopefully the criminal action very soon.''