Telephone Murder.

A homicidal maniac known as the 'tail', dressed in a clown mask, raping and killing a number of girls who work in erotic phone lines. The case has been assigned two policewomen, Lorraine and Consuelo, who begins to investigate, by phone sex, where they are to interview the victim's friends. After the second telecommunications operator, is murdered, his mind and Consuelo & Lorraine to take a job at the hot line.