Cassandra Williams, 14, died last April after overdosing on ecstasy pills. (Courtesy of Angela Eyre)

An 18-year-old Edmonton man who sold the ecstasy pills that caused a fatal overdose in a teenage girl was sentenced to 80 days in jail Friday.

Cassandra Williams, 14, took the drugs last April and fell ill at a dance party for teens at the indoor Galaxyland Amusement Park in West Edmonton Mall. She had obtained the ecstasy through a friend who bought the pills from the teenage dealer.

Williams was rushed to hospital, where she died the next day surrounded by family members.

Police arrested a male teenager shortly after the incident. He pleaded guilty to drug trafficking earlier this year.

The teen, who was under 18 at the time of the offence and cannot be identified under provisions in the Youth Criminal Justice Act, will spend 80 days in jail and another 40 days under house arrest.

Friends and family of the dead girl attended Friday's sentencing.

Before the teen was taken away in handcuffs, he asked members of Williams's family for forgiveness.

Cassandra's mother, Angela Eyre, said she has forgiven him.

"Thank God it's over," Eyre said. "I can get on with my life. I can now actually probably deal with her death. I have yet to do that."