Now he has been charged with supplying the drug.

Police say Janie Panton Roberts, 21, and Mr Duffy, 19, a bartender from the Central Coast, went to a music event at the Petersham Inn in Sydney's west on June 4.

Police allege that, at some point, Mr Duffy bought three to four capsules of MDMA.

He allegedly gave some to Ms Roberts as the two partied.

The next morning, the pair were at a house in Addison Road, Marrickville, when Ms Roberts fell ill.

Paramedics were called at 8.35am but, by the time they arrived, Ms Roberts had died.

Friends remembered Ms Roberts, a former Mackellar Girls School student, for her infectious laugh.

"I'll always remember you and that bloody laugh lol think everyone will never forget that laugh haha," friend Latesha Ah-Kam Leo wrote on Facebook.

"You're now in good hands with our Heavenly Father. Rest in peace Jainie Panton."

Ms Roberts' uncle wrote: "I cannot reach you, but my wishes and prayers shall always touch you and keep you blessed and protected.

"You were loved before; We love you now; and we will love you always."

In June, Mr Duffy posted a picture of the pair on a swing, captioned with a love heart.

On Wednesday, Marrickville detectives charged him by way of a court attendance notice with drug supply.

He is due in Newtown Local Court on October 10.

It comes after Sylvia Choi, 26, died last November after taking drugs at Stereosonic music festival.

Her friend and fellow pharmacist was later convicted of supplying her with an ecstasy pill and MDMA capsule before her death.

Also in June this year, David Gallagher, 24, died at a bush dance party on the NSW North Coast.