Investigating judge Zdenko Posavec turned down the request to place the independent MP in custody, explaining that evidence of his alleged influence on witnesses was not sufficient to remand him in custody.
The Zagreb County Prosecutor's Office backed its motion with reports of Glavas exerting pressure on four witnesses in the case.
Zagreb County Court spokesman and investigating judge Kresimir Devcic said that Judge Posavec stated in his decision that he had heard 24 witnesses in the case so far and that none of them had complained about being exposed to pressure by Glavas or anyone else. Among those witnesses were also the witnesses who the prosecution claims have been influenced by Glavas.
Posavec concluded that there was no fear that the investigation into Glavas and the second suspect, Krunoslav Fehir, launched in June, could be jeopardised by tampering with witnesses.
The prosecution has two days to appeal against the decision with the Zagreb County Court, whose decision will be final.
The Zagreb County Prosecutor's Office has so far requested twice that Glavas be placed in custody, but both motions were turned down, as were the subsequent appeals.
Glavas is charged with ordering the ill-treatment and murder of Serb civilians Cedomir Vuckovic and Djordje Petkovic and the torture of three other Serb civilians.
The other suspect, Krunoslav Fehir, is suspected of ill-treating and shooting at an imprisoned civilian. He admitted to the crime before the investigating judge and accused Glavas of ordering the crime.