Return of security deposit

[Marcus Hendren]

Going to attempt to be brief yet get all the details: Bought a turnkey property rented to 5 student tenants starting a 12 month lease from Aug 2014 to July 2015. 4 moved in and one apparently got kicked out of school and did not move in. He was uncooperative in communicating with me when I was searching for another tenant to replace him. When I did find a new tenant, I signed a completely new lease with him starting in September, immediately collected one months rent and a prorated security deposit. Uncooperative tenant's portion of the rent was not paid for august, but security deposit equals the missing amount. Now the uncooperative tenant wants his security deposit back. Do I return?