De Santis, 33, and Manta, 30, were found dead in their apartment building in the Apulian city of Lecce on September 21, following reports of screams from nearby properties.

According to Italian daily La Repubblica, De Santis’ body was found on the second-floor staircase of their apartment complex, with Manta’s discovered inside their home.

Initial reports suggest witnesses saw a man with a backpack leaving the scene with a knife in his hand.

Italian police on Tuesday arrested Antonio De Marco, a 21-year-old nursing student who used to live with the victims.

Sources at the prosecutor’s office said De Marco had confessed to the double murder, which was described as “cruel and with the total absence of any feeling of compassion towards others”.

According to prosecutors, after stabbing the victims several times in their home, De Marco followed them as they desperately tried to escape before killing them on the stairway of the building they lived in.

Prosecutors suspect De Marco had planned the murder long before committing it. 

As the investigation continues, tributes have flooded in for the young couple.

“No words can express the grief of the Pro Liga, its officials, clubs and players for the premature death of referee Daniele De Santis and his partner Eleonora,” Francesco Ghirelli, president of Italy’s Serie C said on Twitter.

“We remember his smile when on the pitch and his passion for Serie C, which he regarded as a family.

“Violence destroys, and it has taken away two young people with hopes and dreams.

“It is the number one enemy to oppose in all its forms.”

De Santis had officiated 130 professional football matches and was due to be the man in the middle for the first-round Coppa Italia affair between Monopoli and Modena, which took place two days after his death.

With ANSA