Task: Question Answering
Input (English): Passage: In Verona Beach, the Capulets and Montagues are rivals. The animosity of the older generation—Fulgencio and Gloria Capulet and Ted and Caroline Montague—is felt by their younger relatives. A gunfight between Montagues led by Benvolio, Romeo's cousin, and Capulets led by Tybalt, Juliet's cousin, creates chaos in the city. The Chief of Police, Captain Prince, reprimands the families, warning them that their lives "shall pay the forfeit of the peace".
Benvolio and Romeo learn of a Capulet party that evening which they decide to gate-crash. Romeo agrees on hearing that Rosaline, with whom he is in love, is attending. They meet their friend, Mercutio, who has tickets to the party, and Romeo takes ecstasy as they proceed to the Capulet mansion. The effects of the drug and the party overwhelm Romeo, who goes to the restroom. While admiring an aquarium, he sees Juliet on the other side, and the two instantly fall in love, both unaware who the other is. Tybalt spots Romeo and vows to kill him for invading his family's home.
After Romeo leaves the party, he and Juliet each learn that they belong to feuding families, but Romeo sneaks back to see her. Juliet tells him that if he sends word by the following day, they will be betrothed. The next day, Romeo asks Father Laurence to marry them, and he agrees, hoping their marriage will end the feud. Romeo passes the word on via Juliet's nurse and the lovers are married.
Tybalt encounters Mercutio and Romeo at the beach. Romeo attempts to make peace, but Tybalt assaults him. Mercutio intervenes and is about to kill Tybalt when Romeo stops him. Tybalt uses the opportunity to inflict a deadly wound on Mercutio, who curses both houses before dying. Enraged, Romeo chases after a fleeing Tybalt and guns him down. 
Question: Who are the families that the chief of police warns?
Output (English): Capulet.