Tunisia opened a probe Tuesday after a controversial television personality said he had "revelations" about the assassinations of opposition politicians Chokri Belaid and Mohamed Brahmi, a judicial source said.
"A judicial investigation was opened today by the judicial division for the fight against terrorism" after statements by Moez Ben Gharbia, owner of the private channel Attasiaa TV, the source told AFP.
In a video posted online, Ben Gharbia said he had "all the information about those who... killed Chokri Belaid and Mohamed Brahmi", two leftist politicians murdered on February 6 and July 25, 2013 outside their homes.
Media reports said Ben Gharbia made the recording from Switzerland, and claimed that he too had been the target of "attempted murder" last Tuesday because of information in his possession.
"Anyone who knows the truth about these deaths will be murdered," Ben Gharbia said.
His video was posted ahead of a new hearing on October 30 in the trial of 24 Tunisians accused of involvement in the Belaid killing.
Radio Mosaique FM, citing Attasiaa's executive director, said Ben Gharbia would be returning to Tunisia Sunday.
The authorities blamed Belaid's murder on jihadists.
On February 6 last year, authorities said his suspected Islamist assassin, Kamel Gadhgadhi, had been killed in a police raid.
Last December, jihadists linked to the Islamic State group said they were behind the murders of both Belaid and Brahmi.
Belaid's family has repeatedly demanded the full truth behind his killing.
At a news conference Tuesday, his widow, Basma Khalfaoui, called on Ben Gharbia to hand over his evidence to the authorities.
On March 18, Ben Gharbia was given a six-month suspended sentence for identity theft, embezzlement and insulting the head of state.