Besides, the authorities also temporarily banned the work of the brewery in this city 50 kilometres south of Zagreb. The 150-year-old brewery is now owned by the Heineken Group.
The judge refused the request of the prosecution for the detention of the suspects in custody, with an explanation that they could not tamper with possible evidence or affect the probe.
The chairwoman of the Karlovacka brewery managing board, Dutch Moniqe Peters, issued a statement today saying that she "welcomes the continuation of the investigation that would contribute to the eventual understanding of causes and responsibility for the unfortunate event in which Zdravko Martinovic got hurt."
In case the outcome of the legal proceedings show that the brewery is responsible, the company will assume all consequences, Mrs. Peters said adding that the brewery "is continuing to cooperate with all relevant institutions and is carrying out an internal investigation".
While taking a walk near the canal outside the brewery on 23 February the 64-year-old Martinovic fell into a coma and his dog died on the spot. Preliminary check-ups showed that Martinovic had a high concentration of ammonia in his blood.
Martinovic is still in the intensive care of the Karlovac hospital, as his condition has not been improved since then.
At the beginning, the brewery vehemently denied any responsibility for this ecological accident.
On 2 March, the investigating judge Jasminka Jerinic Musnjak ordered an on-the-scene investigation in the brewery.
On the same day, Croatia's chief state prosecutor, Mladen Bajic, said some serious omissions had been made in the process of the reporting this ecological accident.
Later that day, the Karlovacka Pivovara said that an internal inquiry in the brewery had established that amounts of carbon dioxide, a by-product of fermentation processes in the plant, ended up in the canal with sewage, instead of being emitted high in the air. That's why the brewery has also launched the internal inquiry to establish how the CO2 had reached the sewage, contrary to its safety and environmental regulations.