diff --git a/contracts/Distributor.sol b/contracts/Distributor.sol
index bc4e49f..5f342dc 100644
--- a/contracts/Distributor.sol
+++ b/contracts/Distributor.sol
@@ -230,8 +230,9 @@ contract Distributor is UUPSHelper {
 
     /// @notice Freezes the Merkle tree update until the dispute is resolved
     /// @dev Requires a deposit of `disputeToken` that'll be slashed if the dispute is not accepted
-    /// @dev It is only possible to create a dispute for `disputePeriod` after each tree update
+    /// @dev It is only possible to create a dispute within `disputePeriod` after each tree update
     function disputeTree(string memory reason) external {
+        if (disputer != address(0)) revert UnresolvedDispute();
         if (block.timestamp >= endOfDisputePeriod) revert InvalidDispute();
         IERC20(disputeToken).safeTransferFrom(msg.sender, address(this), disputeAmount);
         disputer = msg.sender;