Daniel's exceptional success and absolute honesty made him a prime target. The kingdom's high-ranking ministers grew intensely jealous of him and conspired to strip him of his position, and ultimately, his life [חומת אנך, יוסף אבן יחיא]. This deep resentment was fueled by Daniel's outsider status; he did not belong to their exclusive social circles. Furthermore, he maintained strict oversight over the kingdom's finances, taxes, and military operations, preventing the other officials from doing whatever they pleased [ביאור שטיינזלץ].
Driven by envy, the ministers began searching for any possible pretext or false charge to use against him [רש״י, מצודת ציון, ביאור שטיינזלץ]. They wanted to convince the king that Daniel was embezzling funds or failing in his duties, hoping to show that he made the same mistakes they often did [יוסף אבן יחיא]. They focused their investigation entirely on his administration of state affairs, scouring his records for any sign of financial irregularity, bribery, deceit, or even the slightest hint of rebellion against the current king [מלבי״ם, אלשיך].
Despite their exhaustive efforts, the investigation turned up absolutely nothing. The ministers were completely unable to find any intentional corruption or even a minor, unintentional mistake [אלשיך, מלבי״ם, מצודת ציון]. Their inability to bring him down stemmed from a combination of factors. First, Daniel was entirely loyal and trustworthy. His public reputation was so flawless that the ministers could not even fabricate a lie about him, knowing that no one would ever believe it [מלבי״ם]. Second, their probe extended beyond his current duties, digging deep into his past service under previous kings, yet they still found his record completely spotless [אלשיך].
Daniel's integrity was so profound that fault could not be found anywhere near him. This meant that he never committed a wrong directly, nor did any of his orders or decisions ever indirectly cause the kingdom any damage or financial loss [חומת אנך]. Having completely failed to find any professional or personal flaw in his conduct, the ministers realized they had only one path forward. If they wanted to destroy Daniel, they would have to find a way to use his devotion to the laws of his God against him [מלבי״ם].