EXETER, N.H. (AP) _ A high school teacher worried that her dog would be harmed psychologically if it watched her teen-age lover kill her husband, a prosecution witness testified Friday.

''She told Bill not to kill Greg in front of the dog because it would traumatize the dog,'' Cecelia Pierce said.

The dialogue between William Flynn and teacher Pamela Smart took place a short time before Gregory Smart, 24, was fatally shot in the couple's condominium, said Pierce, the teacher's 16-year-old intern and confidante.

Pierce said she was present during the conversation.

Pierce also testified that Smart told her at school on May 1, the day of the slaying, ''that Bill was going to go up there and he was going to kill Greg'' that night.

Flynn has admitted to the killing. Smart, 23, is charged with planning and abetting the murder because she feared losing everything, including her small dog, Halie, if she divorced. She faces a maximum possible sentence of life in prison without parole if convicted.

The prosecution rested on Friday. The defense is to begin presenting its case to the Superior Court jury on Monday.

The defense says Flynn and two friends killed Smart on their own, then framed his widow to avoid life in prison. In plea bargains, the three Seabrook teen-agers face minimum prison sentences of 18 to 28 years in return for their testimony.

Prosecutors say Smart seduced Flynn, then 15, and later threatened to end their affair unless he killed her husband, an insurance salesman.

Pierce's testimony about Smart's Shih-Tzu dog, named after the rock band Van Halen, recalled testimony last week by Patrick Randall, 17, a confessed accomplice to the slaying.

Randall said that in a final planning session hours before the killing, Smart urged the teen-agers not to hurt Halie and not to get blood on her sofa.

Pierce said she scoffed when Smart told her two months before the slaying that she was in love with her young student.

''She just kept telling me over and over again that she was serious,'' Pierce said.

Questioned by defense lawyer Mark Sisti, Pierce acknowledged trying to help Flynn get a gun. Sisti tried to show that Pierce concealed her involvement in by blaming Smart.

Sisti asked why Pierce didn't go to the police to prevent the killing.

''I didn't think they were going to kill Greg whether they had a firearm or not,'' she responded. ''I believe Pam thought it was going to happen, but I didn't believe the boys were going to do it.''

Pierce said she signed a contract with a Hollywood company, which paid her $2,000 last fall and promised her $100,000 if the company made a movie about the case.