Keith Schembri, the former chief of staff of former Prime Minister Joseph Muscat, will finally testify in the police’s compilation of evidence against Daphne Caruana Galizia murder suspect Yorgen at 10am.

From a missing mobile phone to several mentions in state witness Melvin Theuma’s secret tapes, Schembri has hung over this case like a spectre with his links to the murder and its participants growing after every sitting.

However, Schembri is not the only significant witness facing the courts. Adrian Vella, the mutual doctor of Fenech and Schembri, is also taking the stand.

Vella has confirmed with investigators that he passed on several letters between Fenech and Schembri while the former was under police bail, including this one. However, he has maintained that he never read the content of the letters.

One of the letters was an alleged frame-up attempt on Chris Cardona from Fenech and Schembri.

Vella was also involved in Fenech’s escape plot before his arrest.