Six suspects have been released from "investigative detention" in a €162m ($181m) fraud probe involving troubled Croatian shipbuilder Uljanik Group.

The county court in Rijeka made the order on Monday, the Hina news agency said.

Court spokesman Zoran Srsen said that there were no longer grounds for detention because all the witnesses had been interviewed during the investigation.

The six are former Uljanik Group management board chair Gianni Rossanda; its former management board members Marinko Brgic and Veljko Grbac; Maksimilijan Percan, ex-chairman of subsidiary yard 3 Maj; former Uljanik Plovidba director Dragutin Pavletic...