See the lease provisions for notice and strictly comply if possible. If the person to whom notice is owed is the deceased lanlord (and not a management company), make a demand to the representative of the estate. Also see http://www.statutes.legis.state.tx.us/Docs/PR/htm/PR.92.htm#92.003. Also see http://www.statutes.legis.state.tx.us/Docs/PR/htm/PR.92.htm#92.103. You could be entitled to more than the return of the security deposit, including attorney's fees.
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