The Interior Ministry continues its investigation of alleged match fixing and illegal betting in the Bulgarian football on Thursday.

It is expected that football players from the A Football Group will be interrogated in different towns, private NOVA TV reports.

It is still unclear whether the nine people that were detained for 24 hours during Wednesday's operation of the Criminal Police will remain in custody.

The Interior Ministry announced on Wednesday that during the operation items and documents proving the criminal activity of the group were seized.

The investigation is under the guidance and supervision of the specialised prosecution.

According to Gong.bg, the defender of the Bulgarian national team and second captain of current A Group leaders CSKA Aleksander Tunchev, top scorer of Lokomotiv Plovdiv Martin Kamburov, and Cherno More defender Kiril Kotev, have been detained during the operation of the Interior Ministry.

Among the interrogated are football players, managers and referees.

According to NOVA TV, the main focus is on players of Lokomotiv Plovdiv in the period during which Konstantin Dinev was owner of the club.

Former player Yordan Todorov, as well as Martin Kamburov and Yordan Gospodinov, who still play for the team from Plovdiv have been interrogated.

The specialised operation started on December 9, with the Interior Ministry carrying out interrogation of witnesses, searches and seizures in six Bulgarian towns.

The investigation started after the Union of European Football Associations (UEFA) submitted a signal to the Bulgarian Football Union (BFS).

A representative of UEFA said for the Bulgarian National Television that this was one of the largest operations in the last years.

According to private bTV station, the teams accused in match-fixing are Lokomotiv Plovdiv and former A Group competitors Lyubimets.

The investigators have several recordings, including a conversation between Martin Kamburov and his brother, in which the two discuss football bets.

The President of BFS Borislav Mikhailov announced on Wednesday that no players in the national team were involved in match fixing.

The former national coach Plamen Markov said for the Bulgarian National Television on Thursday that the involvement of the police was a good sign that Bulgarian football will be cleansed, while footballers will know the consequences of such criminal moves.

Markov reminded that previously when UEFA had submitted signals of match fixing in Bulgaria, BFS promised to investigate the cases, but to no effect.

This is not the first scandal with match fixing in Bulgaria, as earlier this year three players from the junior national team were suspended over allegations that they were involved in manipulations.