Vilnītis, regarded as a hapless and unpopular figure in the office, headed KNAB from March 2009 to June 2011 when he was dismissed by the Saeima.
His years at KNAB were marked by infighting, particularly with deputy Juta Strīķe, now a New Conservative Party MP, and a general impression what far less was happening on the anti-corruption front than should probably have been the case. The office's work would continue to be regarded as close to paralyzed under Vilnītis' replacement, Jaroslavs Streļčenoks who also fought a long-running battle with Strīķe.
In 2014 KNAB started a check following claims by Vilnītis that Strīķe had had information over a corrupt high-ranking official but chose not to act on it. Appearing on commercial LNT television, Vilnītis accused Strīķe of a dazzling array of crimes, none of which have been proven.
In 2017 Vilnītis ran in the municipal elections under the ticket of the Latvian Social Democratic Workers' Party but did not get elected. In his election declaration he was listed as chairman of a company called "Information Agency" Limited, a private detective agency previously known as "Atroms". The company's website boasts of its connections to a UK investigative firm, BGP Global Services. and of its ability to expose fraudulent schemes.