The anguish was more than enough for Tony and Mary Scrocca to handle when they found out that their first-born son -- usually the most animated person in any group -- was killed in a fire just off the University of Maryland campus six weeks ago.

But then to learn that the blaze was deliberately set at his College Park house, and to not know who did such a thing, has turned into a slow form of torture for the New Jersey couple.

"We're trying to piece everything together little by little," Tony Scrocca said yesterday at Prince George's County police headquarters, where he pleaded for information that would help solve his son's case.

Detectives have interviewed more than 20 college students who were at a party at Michael Scrocca's three-story rented house in the early-morning hours of April 30, when the fire was set. But they say it still is a mystery who poured gasoline from a red plastic can around the house at 4 a.m., when everyone was sleeping, and started a fire, killing Scrocca, 22, and injuring his housemate, Stephen Aarons, 21.

After four years at college, Michael Scrocca was three weeks away from moving back home for a job in New Jersey at Johnson & Johnson, 20 minutes from his childhood home.

Most of his possessions burned in the house, so his parents don't even have those to hold onto.

"Some days all we do is talk about it, and some days all we do is cry," Mary Scrocca said.

The couple drove from their home in Branchburg, N.J., to Palmer Park yesterday to talk to the media in hopes of a break in the case.

They laid out dozens of bright pictures of the handsome young man on a round table. There's his smiling face as a baby, there's the boy sitting on Santa's lap, with his friends at the beach, at his younger brother's high school graduation, posing with bullfighters in Spain, surrounded by buddies and beautiful women.

Michael Scrocca, a senior finance major, was the kind of person who played five intramural sports, knew bartenders by name and would run to Atlantic City for an overnight trip with five minutes' lead time if you asked him to, his family said.

"His friends said he flew by the seat of everybody else's pants," his father said. "He was very lively. He was always ready to go, always ready for an adventure."

He also was brainy, his parents said proudly, noting that he got a near-perfect score on the math portion of the SAT. "He was a math kid," his mother said.

Mary Scrocca said she will never find closure. But to respect his memory, and for her own peace of mind, she would like to know who set the fire.

"With Michael's personality, he would never rest until we found out who did this," she said. She said an answer also is crucially important to her younger son, Brian, 21, who was extremely close to his brother.

Mary Scrocca said she doesn't believe the person who set the fire intended to kill her son. "We don't know why the person did it. Maybe they were just drunk," she said. "Maybe the person who did it will come forward and tell us. They have to have trouble sleeping at night."

Prince George's homicide Detectives Ben Brown and Chuck Richardson, who are handling the case, said the gas can used to set the fire came from the house next door. It was sitting in the neighbor's yard about 20 feet from the back of the party, where as many as 100 students were drinking beer from kegs and downing shots of alcohol by way of an ice luge.

The gas can was found on the porch of Scrocca's house. The detectives say they are trying to figure out who moved it and how it got on the porch.

Richardson said the detectives are still interviewing students, which is becoming more difficult now that classes have ended and many students are away for the summer.

Mary Scrocca said the idea that her son was killed, especially at the university he loved, has not sunk in yet. She said she feels as if he is still away at college.

"I can't look at his picture and think I'll never see him again," she said. "It doesn't seem real. We're still in shock."

Tony and Mary Scrocca, parents of arson victim Michael Scrocca, talk to the media at Prince George's County police headquarters.