Peaches Geldof Cause of Death -- Heroin Overdose

The coroner has made it official ... Peaches Geldof died from a heroin overdose.

The levels of heroin in Geldof's body were in a "fatal range," and puncture wounds were found on her elbows, wrists and thumbs.

According to police, the heroin found in her home the day of her death tested 61% pure. Typical street heroin is 30%.

Geldof's husband, musician Thomas Cohen, has said Geldof was trying to kick her drug habit and had been taking methadone for 2.5 years.

The 25-year-old Geldof was found dead in her home on April 7.