French police investigating the shooting of a 77-year-old heiress from one of Monaco's richest families have arrested around 20 people, including her daughter and son-in-law, sources close to the probe said.
The heiress, Helene Pastor, died last month from multiple wounds to the abdomen, neck and face, two weeks after she was shot as she was leaving a hospital in the French Riviera city of Nice. She had spent two hours before the attack at the bedside of her son, who had suffered a stroke.
Her chauffeur, Mohammed Darwich, 64, also died from injuries sustained in the attack.
The arrests were made in Nice, the southern city of Marseille and Rennes, in the west of France, according to several sources.
The Paris-based lawyer for the family made no comment.
The daughter, Sylvia Pastor, is married to Wojciech Janowski, the honorary consul of Poland in Monaco.
The attacker used a sawn-off shotgun and fired several shots before escaping with an accomplice.
Pastor had inherited a huge real estate and construction business set up by her Italian grandfather Jean-Baptiste Pastor, a stone mason who came to Monaco in 1880.
As the sleepy principality in the French Riviera slowly grew into a playground for the world's rich and famous, the family fortunes skyrocketed.
But the real windfall came in 1966 when Prince Rainier, whose wedding to Hollywood actress Grace Kelly helped catapult Monaco to international fame, gave permission to Helene Pastor's father Gildo to build high-rise buildings along the seafront.
After the shooting, French prosecutors opened a judicial investigation into attempted murder but investigators have had few leads thus far.
Police had previously arrested a man who called the Pastor family several times after the shooting, claiming to know the identity of the mastermind and offering to divulge the information in exchange for cash.
A court has ordered that he undergo psychiatric tests.