Who should have the security deposit now that the lease is up?

I originally (and regretfully) signed a lease with two other tenants for a 3 bedroom apartment. Upon signing, I issued a check in my name for a first month, last month, and a full security. The other tenants reimbursed me in cash. Following this payment, every other payment was made from my name, with the other tenants paying me in cash. Four months before the lease ended, both tenants broke lease and left without warning. Knowing that I was liable for the full rent regardless, I decided to pay their part of the rent in addition to my own, and I would reimburse myself when their portion of the security deposit was issued back to me. Now that I have moved out, one of the other tenants has contacted the landlord and wants his third of the security deposit back. He has cost me far more than this in past due rent, utilities, etc. My question is, considering all payments were made from beginning to end from my name to the landlord, does the landlord have any right to issue it to him? Shouldn't I technically receive the entire security deposit check regardless of what the other tenant wishes? Thank You.