How to evict an anti-social tenant quickly?

Other

I have a shared student house with 4 tenants on a single tenancy agreement, consisting of 3 women and 1 man.

The man appears to have have had some sort of mental breakdown and has trashed the house on at least two occasions, injuring himself and damaging fixtures and fittings. The the police and paramedics attended on each occasion and took him away but they released him and he has returned to the house.

The other tenants (all women) are now very frightened to be in the house alone and are mkaing arrangements to be out for most of the day and are trying to ensure that they are never alone in the house with the guy.

They have turned to me to get the guy to leave asap but I don't know how to help them without breaking the law myself and possibly leaving myself open to being sued for unlawful eviction.

How can I get this guy out of the house asap? There is another 3 months left on the tenancy agreement.