Cerniauskas, who received the Medal of the Order of the Lithuanian Grand Duke Gediminas in February 2018, was removed from the list for discrediting the name of an awardee, it said.
The journalist said on Wednesday he had produced analyses on public figures and businesses to a PR company without informing 15min.
He said he had done the analyses for Darius Gudelis' Bureau. Gudelis is board chairman at Vipcommunications (VIP Viesosios Informacijos Partneriai, or VIP Public Information Partners).
15min said on Wednesday it had sent information on Cerniauskas' private information collection activity to law-enforcement officials.
Ramunas Saucikovas, CEO of the news site, said an internal investigation had revealed that the journalist's activity might have "run counter not only to journalist ethics but also to laws".