Dutch vehicle authorities said Monday that carmakers Suzuki and Fiat Chrysler were being referred to the public prosecutor for possibly misusing emissions software.
The Netherlands Vehicle Authority (RDW) revealed its findings in its second report since the so-called Dieselgate scandal erupted two years ago.
Volkswagen admitted in September 2015 that it had installed software devices in 11 million diesel-engine cars worldwide that reduced emissions of harmful nitrogen oxides (NOx) when the devices detected the vehicle was undergoing tests.
The RDW said in its report on Monday that it had found Suzuki's Vitara and Chrysler's Jeep Grand Cherokee "had higher NOx emissions than could be justified".
The authority had re-tested 16 vehicle types whose emission control systems had shown possible discrepancies.
Further tests on 14 cars had concluded that the "reduced performance of the emission control system was permissible to protect the engine".
But in the case of the remaining two vehicles, the Suzuki and the Jeep, "it was not plausible that the reduced efficiency of the emissions control system was in order to protect the engine" and "further research" was needed.
In the case of the Suzuki, the authority concluded that there appeared to be some kind of "tool for unauthorised manipulations" of the emissions.
"The RDW has informed the public prosecutor about these vehicles," it said, adding it would determine whether any criminal offence has been committed as it was "not permissible" to have unexplained high emissions of toxic gases.
VW faces an array of legal challenges in Germany and worldwide relating to the software, installed mainly in own-brand vehicles but also in cars made by Audi, Skoda and Seat, among its stable of 12 brands.
In total, Volkswagen has agreed to pay some $23 billion in the United States to compensate some 600,000 US car owners.
In May, US environmental regulators filed a lawsuit against automaker Fiat Chrysler, accusing it of installing devices on its trucks, that hid harmful emissions during testing.
