NEW YORK (AP) _ The stars who turned out for opening night of Paul Simon's first Broadway musical, ``The Capeman,'' had to pass through an angry relatives of people killed by the show's namesake.

``Other people's tragedy is not entertainment,'' said Donna Krzesinski, whose brother Tony Krzesinski was killed by the real ``Capeman,'' Salvadore Agron. ``If people have a heart, they will not see this play,'' Krzesinski, 37, said as she started to cry.

The musical is based on the life of Agron, who at age 16 stabbed two other 16-year-old boys to death in 1959, thinking they were members of a rival gang. The theater is just a few blocks east of Hell's Kitchen, the working-class neighborhood where the boys were killed.

Parents of Murdered Children, based in Cincinnati, organized a demonstration of about 60 people outside the Times Square theater where Simon's $11 million production opened Thursday night.

Kim Erker, a cousin of the other Agron victim, Bobby Young, urged celebrities arriving at the show to boycott it.

``Look at Bill Cosby,'' Erker said. ``Would you make a musical off of that tragedy?''

Among those attending the premiere were Rita Moreno, Jimmy Smits, Penny Marshall, Julia Roberts and Mark Wahlberg.

``I'm keeping an open mind,'' Tony Award-winning actor Jerry Orbach said as he went into the theater.

John Barbour, a spokesman for show producer Dan Klores, had no immediate response to the protest.

Simon does not perform in the musical, which features 38 new compositions he wrote. The songs chronicle Agron's troubled childhood in Puerto Rico, the much-publicized slayings and his 20-year imprisonment and eventual parole.

Agron, a member of a street gang called The Vampires, was dubbed ``The Capeman'' in newspaper headlines because he reportedly draped a black cape lined with red satin across his shoulders the night of the murders.

He and a fellow Vampire, Luis Hernandez, were looking for an Irish gang dubbed the Norsemen. But the boys who died were not gang members. After his arrest, Agron reportedly dared authorities to execute him.

Agron became the youngest man ever on New York state's death row. His sentence was commuted to life in prison in 1962 by Gov. Nelson Rockefeller. He was later paroled and at 43, died of a heart attack in 1986.