ROME, Italy (AP) -- Two members of a heavy metal group called the "Beasts of Satan" who confessed to taking part in three ritual Satanic slayings were sentenced to prison Tuesday, and a third defendant was acquitted, Italian media reported.

Andrea Volpe, Pietro Guerrieri and Mario Maccione had confessed to roles in the grisly 1998 killings of Chiara Marino, 19, and Fabio Tollis, 16, in the woods outside of Milan. Five other members of their suspected Satanic cult have been ordered to stand trial in June.

Volpe, considered the mastermind of the ritual killings, was sentenced to 30 years in prison -- 10 more than prosecutors had asked for, the ANSA news agency said. Guerrieri was given 16 years in prison, and Maccione -- who authorities said played secondary role in the murders -- was cleared, according to the report.

Prosecutors said the suspects belonged to an occult sect that carried out the January 1998 killings in a drug-fueled Satanic ritual in woods near Somma Lombardo, northwest of Milan. Marino was stabbed to death and Tollis, her boyfriend, was killed and buried next to each other.

Authorities say they had tried once before to kill the two by burning them alive in a car on New Year's Eve.

In the third slaying in January 2004, Mariangela Pezzotta -- Volpe's girlfriend -- was shot and then buried alive. The Pezzotta case led authorities to the buried remains of Tollis and Marino.

The cult members also stand accused of pushing a boy to commit suicide.

Prosecutors asked for relatively light prison terms because the suspects cooperated with the investigation and expressed remorse. Prosecutors and court officials were not immediately available for comment after the ruling Tuesday.

Relatives of the victims expressed outrage that prosecutors did not seek life terms.

"They are murderers," Lina Marino, mother of Chiara Marino, told Italian television reporters. "It's not fair."

The verdict comes amid growing concern in Italy that young people are turning to Satanism and the occult. On Thursday, a Vatican-linked university opened a two-month course on diabolical possession and exorcism.