Nobody ever really believed that Francesco Cenci's death was an accident.
On September 10, 1598, his body was found with a smashed skull outside the family castle in Petrella Del Santo (near Rome) and authorities were immediately suspicious. It was well known that Francesco Cenci had numerous enemies, not the least of which were his own children. His notorious reputation had gotten him in trouble with the Church on various occasions but his position as a wealthy aristocrat had always kept him safe. Francesco's cruelty towards his five children and his second wife, Lucrezia Petroni, was well known and he had often vowed that he would outlive them all (he may have had a hand in the death of at least one of his sons). Other rumours of dark deeds surrounded him, especially concerning his relationship with his daughter Beatrice.
Born in 1577, any hope that Beatrice might have had of marrying out of the family the way that her older sister did was crushed by Francesco's determination to keep her under his control. It's hard to separate truth from lurid fiction at this point but at least some sources claim that he abused Beatrice sexually. Francesco was furious when she tried to lay a complaint against him and he sent Beatrice and her stepmother into exile away from Rome.
We'll never know exactly when Beatrice, Lucrezia and the surviving Cenci sons, Giacomo and Bernardo, first decided to kill Francesco. The testimony in the case is probably unreliable since most of it was gained through torture (even though it was enough for conviction) but there is little else available. The murder was apparently carried out with the help of Abbe Guerra (a clergyman who was in love with Beatrice). After a poisoning attempt failed, the family eventually smashed Francesco's skull and threw him off a balcony to make it look like an accident. Beatrice and Lucrezia played their parts perfectly and an elaborate funeral was later held.
Pope Clement VIII remained suspicious and arranged for the body to be exhumed so that a medical examination could be made. The disappearance of Abbe Guerra (he had escaped before he could be arrested) and the death of an assassin who had assisted in the murder helped build the case against the family members. I'll spare you the details of the various torture methods that were available at the time but they have been well documented elsewhere. Although Giacomo and Lucrezia eventually confessed, Beatrice was able to resist until she was confronted with the testimony of the others. All of the family members involved in the murder, including 12-year old Bernardo Cenci, were sentenced to death. Pope Clement rejected any plea for mercy and ordered the sentences to be carried out.
On September 10, 1599, the entire family received their final sacraments before being taken to Piazza Castel Sant'Angela in Rome for the execution. Despite a last-minute pardon for Bernardo, he was forced to watch as all the others were executed (he collapsed as Beatrice was led to the scaffold but was revived). Beatrice and Lucrezia were beheaded while Giacomo (whose body bore clear marks of torture) was beheaded, drawn and quartered (the pieces were hung from butcher's blocks). The bodies were kept on display in the Piazza until evening and then released for burial. Beatrice's body was carried in a procession down to the the church of San Pietro in Montorio where she had asked to be buried. It was a day-long spectacle and several of those attending died from heat stroke.
To nobody's surprise, the bulk of the Cenci fortune vanished into the coffers of the Pope's supporters (Bernardo was forced to pay a substantial fine as a condition of his pardon). Aside from Bernardo and Giacomo's children, the Cenci family was largely wiped out but the legends surrounding Beatrice Cenci lived on. According to at least one account, the two executioners who had carried out the death sentences died within a month of her death (one by suicide, the other by murder). She became a figure of legend with stories of her haunting the piazza where she died on each anniversary of her death.
The story of Beatrice Cenci has been appeared in numerous books, plays, an opera and a movie. Percey Bysshe Shelley, Alexander Dumas (pere), Nathaniel Hawthorne and Stendhal wrote extensively about the lurid crime associated with her name. The tragedy has a sadly modern ring to it since domestic violence and parental abuse continue even today. All too often, victims still resort to violence to protect themselves from their abusers, especially when they are given no other options. While some progress has been made, it's still not nearly enough to prevent other domestic tragedies from happening.
Visitors to Rome can still see the haunting portrait of Beatrice (reportedly painted shortly after her death) hanging in Rome's Barberini gallery in addition to her tomb and the Palazzo Cenci where she lived. The executioner's blade that beheaded her is on display in Rome's Criminology Museum. They are fitting reminders about a tragic story and it's brutal ending.