LA fears it will be overwhelmed by Jackson fans

Police confirm drugs discovery two days before singer is due to be buried at Hollywood cemetery

There were growing concerns yesterday that Los Angeles could be overwhelmed as hundreds of thousands of fans flock to Michael Jackson's memorial service.

The singer's funeral is expected to take place at Forest Lawn Memorial Park in Hollywood on Tuesday. A memorial service will also take place that morning at the Staples Center, a Los Angeles sports and entertainment arena owned by AEG, which was promoting Jackson's scheduled comeback concerts in London. More than 1.2 million people around the world registered online for 17,500 free tickets for the downtown memorial. Within minutes of the lottery opening for business, its server crashed.

Assistant Police Chief Earl Paysinger said up to 700,000 people could try to reach the arena. A wide area around the venue will be blocked off, and more than 1,400 police officers have been asked to volunteer for duty on Monday and Tuesday. Despite reports to the contrary, AEG's chief executive, Randy Phillips, said the event would be a sober celebration of the singer's life rather than a colourful tribute concert. "This is not a show, it's a service," he said yesterday. "There will be a time to celebrate Michael Jackson, but this is the time to bury him." People without tickets are urged to stay at home and watch the service on television.

News of the fans' interest in the event comes after a law official confirmed that a powerful sedative called Diprivan, which has been linked to sudden cardiac arrests in its use as an anaesthetic, was found at the house where Jackson suffered a fatal heart attack.

The longer-term task for the Los Angeles Police Department (LAPD) will be getting to the bottom of whether anything untoward, by way of use of medicines, helped bring on Jackson's heart attack. Detectives say Diprivan was the most suspicious of an array of prescription medications seized at the property. Also called Propofol, it is widely used to render patients unconscious in operating theatres, but rarely gets administered outside hospital since it must be delivered by intravenous injection. Despite Diprivan being a highly effective treatment for insomnia, incorrect dosages can be very dangerous.

Last autumn, doctors from the Mayo Clinic warned that in rare cases Diprivan can trigger events leading to heart dysfunction and death. They said three patients receiving it to treat severe seizures suffered cardiac arrest, and two died. The clinic stopped using Diprivan to treat such patients. The drug's maker, AstraZeneca, says patients using Diprivan should be monitored, and in a tiny number of cases patients using it have suffered cardiac arrest, but it was not clear the drug was to blame.

The LAPD has called in Drug Enforcement Agency officials, indicating that some form of illegal activity is suspected in the way that painkillers, anti-depressants and sedatives were administered to the singer. Exact details about what caused his final collapse will not become available until either the LA County Coroner or Jackson's family reveal the results of toxicology tests carried out during their separate autopsies. These are expected to take another fortnight to arrive.

Questions continue to be asked of Dr Conrad Murray, the doctor paid $150,000 (£92,000) a month to safeguard the singer's health. Through a lawyer, he has denied prescribing the painkillers OxyContin and Demerol to the singer, but has yet to make a similar statement about Diprivan.