Nah that was a bad rumor, the truth is that universal and the producer are thinking of a polite but good way to put off Paul Walker's character, in other words, get him off the movie series, so they said they are and will use the scenes they have filmed him in (more than half of the movie) and put him off... Justin Beaver won't be in it.
In other words, Universal know what their fans want, and they want something that'll keep the viewers still interested and excited for the movies, another thing, Justin Bieber is no where in the previews, nor extended previews nor is mentioned in ANY of the interviews with universal and producers.. Done and out!
Some are saying his brother will be casted. Also, there are talks of letting paul walker be in the film(the parts that were shot earlier). Will miss him a lot..