It is understood, a local drug dealer from South Dublin has contacted Gardaí to say that Mark Hennessy had attempted to buy cocaine from him on the night Jastine Valdez was murdered.
Gardaí are also said to be investigating whether the suspected killer was using dating apps and if he was stalking the 24-year-old student.
The dad-of-two was shot dead on Sunday night after he was confronted by Gardaí, while Ms Valdez's body was discovered in Rathmichael the next day.
Gardaí have recovered CCTV of Mr Hennessy in a pub in Ballybrack showing him drinking.
The 40-year-old was unsuccessful in buying cocaine from this drug dealer but Gardaí believe he procured cocaine later that night and he continued on a drink and drug binge until confronted in Cherrywood.
A public memorial is being planned for Ms Valdez for next week.
She will be laid to rest in her native Phillipines but plans are underway for a service here also.
A Go Fund Me page set up to help her parents has raised more than €114,000 – far surpassing its original target of €10,000.
Raymond Garrett from Outreach Ireland says the outpouring of support for Jastine’s family has been incredible.
He said: "It is beyond belief how the Irish community, the Filipino community and the country as a whole has shown support.
It is not in any way compensation, it is just the only thing people can do looking on apart from looking on and wishing well, offering support is to give a small donation.
The average donation is €25.
Gardaí are investigating whether the man suspected of abducting and killing Jastine Valdez was stalking her.
The 24-year-old student worked in a cafe in Bray, where dad of two Mark Hennessy lived.
Gardaí are also looking into whether the murder suspect was using dating apps and are examining a smashed up phone believed to have been his.
It is understood Gardaí are investigating whether Mark Hennessy, the man suspected of abducting and killing Jastine Valdez was using dating apps and websites.
Mr Hennessy was shot dead while sitting in his car by a Garda officer on Sunday night - Ms Valdez's body was found in Rathmichael in south Dublin the following day.
Last night Gardaí appealed for information about her handbag and iPad mini.
Gardaí have issued a fresh appeal for help in the Jastine Valdez murder case.
They are seeking the public's assistance in finding her blue shoulder bag and her iPad mini.
The 24-year-old student was abducted in Enniskerry on Saturday and her body was found in Rathmichael on Monday.
Gardaí are also looking for dash cam footage from drivers who were in south county Dublin at the weekend and who may have seen Mark Hennessy's black Nissan Qashqai.
GSOC has revealed that Mr. Hennessy, who is believed to have killed the 24-year-old, was shot dead in the driver's seat of his car by a Garda officer.
Mr Hennessy died from a single gunshot wound to his shoulder which ricocheted into an artery.
A post mortem on the 40-year-old, father of two said that there was a single bullet discharged from the official firearm of the Garda involved and it appears to have hit a bone around his shoulder and ricocheted into the artery causing fatal injuries.
Investigators found a stanley knife in the vehicle, and his body had evidence of self-harming.
Gardaí are also investigating whether he tried to buy cocaine after the death of the 24-year-old student.
GSOC investigators are collecting video footage from a Garda traffic car at the scene, and from CCTV cameras surrounding the area.
An online book of condolence has also been opened on Wicklow.ie along with one at the Powerscourt Arms Hotel in Enniskerry.
Also, donations to the page on the crowdfunding site, gofundme.com, Jastine Valdez Memorial Fund, have reached over €110,000.
People with any information should contact Bray Garda Station on 01-6665300 the Garda Confidential Line 1800 666 111 or any Garda Station.