One of those arrested is a nephew of Amri and two others who are suspected of being part of the same terror cell.
The ministry claimed that Amri sent his 18-year-old nephew Fedi money to join him in Europe. It isn't known if the three suspects helped the jihadi flee Berlin.
Fedi was arrested in Oueslatia, Amri's hometown, and the other two were arrested in Tunis on Saturday.
Amri's fingerprints were found in the semi truck used in the attack. The Islamic State claimed responsibility for the attack.
Amri was stopped by two police officers when they saw him acting suspiciously. He told them he was from southern Italy but his accent gave him away. They asked for ID and he went into his backpack and pulled out a weapon, shot one officer in the shoulder and the other returned fire and shot Amri dead.
Before his death, Amri pledged allegiance to ISIS leader Abu Bakr al-Baghdadi and called for his fellow Muslim jihadists to take revenge on "crusaders" bombing Muslims. He did not mention that "crusaders" bomb Muslims because those Muslims they bomb want to kill them and their families, then take their wives as sex slaves.
Maybe he forgot to mention it in the video--perhaps the camera made him nervous. It isn't known if the video was made before or after Amri killed innocent people in Berlin.
Spain's Interior Minister Juan Ignacio Zoido said police are investigating whether Amri was in contact with another possible extremist in Spain. He told a Spanish radio station Cope that police are looking into a tip passed on by German authorities saying that Amri had made a contact in Spain.
Zoido said that "we are studying all possible connections (between Amri) and our country, above all with one specific person."
Amir had been seen as a potential threat long before the Berlin Christmas market attack, but because his papers weren't in order, they didn't know what to do with him and let him stay in Germany since Tunisia initially denied he was a citizen.
That should tell us something about Tunisia.