One Tenant on App and Lease - Neighbor says 3 are moving in.

[Peter Lambert]

Scenario -

Lease Application for one tenant (checked by our realtor) - great employment history, rental history and credit score. No criminal background. Looked great on paper, and is why we went with this tenant. Signed a Lease beginning Jan 1, 2014, paid security deposit and first month's rent.

Due to working out of town, tenant told me he could not move in for another week. Neighbor contacts me today and tells me he met "one of the new tenants". Apparently three of them are planning on living there.

Still have yet to get ahold of the tenant. Tenant does not have keys yet, house has is still vacant, tenant paid security deposit and one month's rent.

How should I proceed? Run checks on the other two? If they are ok, modify the the lease? I would prefer not to have three guys living in this house. If I went that route I would likely want to increase the rent.

Thoughts?