want someone out of my house

my house is shared with three other lease holders and one of them recently moved in his girlfriend neither me nor the other lease holders want her in our home, she's been here for almost three weeks how can i get her to leave without causing all of us to get evicted for breaking the lease, especially when it was only the one roommate who broke the lease, please email the solution to my problem to cysluvme@yahoo.com, thank you

Based on what you say here, you could file suit against him (or at least threaten to do so) in small claims court or in regular court; filing in small claims court is easier and requires no attorney...you could try to collect all of the costs and damages that you suffered due to his behavior... you may also file eviction papers on her if need be and have a court order her to leave. Or ask the police to remove her--they may do so if she has not lived there long.