The fifth ward is located just outside of downtown. Property values in the area have skyrocketed and continue to climb. The City of Houston offered to purchase the churches. When the churches refused, the city came back with threats of using eminent domain to acquire the property as part of an urban development plan.
More here. Texas state law, written and passed after the Supreme Court decision in Kelo v New London, expressly forbids this kind of eminent domain taking. Moreover, the taking appears to specifically violate the first amendment rights of these two churches.
Quick! Guess what to which political party the Houston mayor belongs!