A 15-year-old Adelphi girl, who police allege offered $5,000 to two teen-age friends to kill her parents, has been charged along with the two youths in the Thursday stabbing death of her father.

Prince George's County police said yesterday that Emilio Casella, 45, was fatally stabbed in the chest at the family's Adelphi home. Casella's wife, Anna, sustained minor injuries after being stabbed in the back.

Police spokesman Bob Law said Lisa Casella, the victim's only child, Daniel Eric Reedy, 15, and Fred Allan Mozingo, 19, were charged yesterday with first degree murder and are being held without bond in the county jail in Upper Marlboro.

Law said police believe the alleged patricide may have stemmed from a smoldering dispute between Lisa Casella and her parents, who objected to her companionship with Reedy.

Neighbors of the Casella family said yesterday that Lisa was a quiet young woman who attended private school and was doted upon by her father. Reedy, they said, did not attend school.

During questioning by police yesterday morning, the three youths gave contradictory accounts of events leading to the stabbing of the elder Casella at 10:20 p.m. Thursday.

According to Law, the stabbing allegedly occurred after Lisa Casella let the two youths into the family home without her parents' knowledge and took them to her bedroom to hide.

Law said the parents were sitting downstairs in the recreation room when Lisa called her father upstairs to fix her television.

When Casella got to the top of the stairs, Law said, one of the youths allegedly clubbed him with a table leg that had lead weights attached to it. The dazed man, staggering, tried to fight back and was then stabbed in the chest, Law said. Police contend that upon hearing the scuffle, Anna Casella came upstairs and was stabbed in the back.

Law said Reedy and Mozingo fled and were arrested several hours later at the Reedy family home, at 9440 Riggs Rd. in Adelphi, where both boys had been living.

Casella and his wife were taken by ambulance to Washington Adventist Hospital. Casella was pronounced dead just before midnight. Anna Casella was treated and released. She was in seclusion yesterday and could not be reached for comment.

Initially, Law said, the teen-agers explained that Lisa Casella let the two boys into the house and that when an argument between Lisa and Reedy ensued, she called her father for help.

Police said the youths originally said that Casella was stabbed during an argument that resulted when he ordered the boys to leave the house.

Law said police allege that Lisa Casella had promised to pay Reedy and Mozingo $5,000 for killing her parents because they disagreed about her association with the boys.

He said there is no indication that Lisa had $5,000.

Yesterday neighbors stood outside of the Casellas' tidy, brick home, shaking their heads at the shocking events that had disturbed their comfortable, quiet neighborhood.

Prentiss Crockett, who lives next door, said that he heard Anna Casella screaming for help from her porch. He said he came outside to see what was going on, then went inside and called an ambulance.

"We thought something was wrong with the daughter ," Crockett said. "She wasn't crying at all; she wasn't hysterical."

Jonna Crockett said Lisa, an only child, always seemed quiet, but very friendly. The Crocketts said they thought the family had lived in the neighborhood for at least 10 years and that Lisa had always attended private schools. She was a student at the Cynthia Warner School in Takoma Park, where officials refused to comment.

Police and family friends also believe that the two boys slashed three tires on Emilio Casella's light green Monte Carlo about two weeks ago.

Yesterday afternoon, the Reedys were gathered at their home within a few miles of where the murder ocurred, waiting to hear from police. Richard Reedy, Eric's father, said that he did not know anything was amiss until police arrived. Reedy, who works at a gun shop, said he was angry that police would not let him see his son.

The elder Reedy said his son attended Buck Lodge Middle School last year, but was unable to attend this year because "he has a hole in his heart and is too young to be operated on."

He said that Mozingo had been living with the family for the last few weeks.

At the Salon Ines in Metzerott Plaza, where Emilio Casella had worked as a hairdresser for the last 10 years, the mood was somber. Shop owner Livio DiBernardo, a family friend, said Casella was dedicated to his daughter. He said Casella had told him recently he was selling his home and moving to Burtonsville with his wife's relatives because he wanted to get his daughter away from bad influences.

DiBernardo shook his head sadly and said, "He was part of my family, part of my life.